diff --git a/frontend/public/locales/en-US/translation.json b/frontend/public/locales/en-US/translation.json
index 944a1df22..00cfe7265 100644
--- a/frontend/public/locales/en-US/translation.json
+++ b/frontend/public/locales/en-US/translation.json
@@ -1737,5 +1737,48 @@
         "text": "To make these permissions unchangeable, use the Add Password tool to set an owner password."
       }
     }
+  },
+  "watermark": {
+    "completed": "Watermark added",
+    "submit": "Add Watermark",
+    "filenamePrefix": "watermarked",
+    "error": {
+      "failed": "An error occurred while adding watermark to the PDF."
+    },
+    "watermarkType": {
+      "text": "Text",
+      "image": "Image"
+    },
+    "settings": {
+      "type": "Watermark Type",
+      "text": {
+        "label": "Watermark Text",
+        "placeholder": "Enter watermark text"
+      },
+      "image": {
+        "label": "Watermark Image",
+        "choose": "Choose Image",
+        "selected": "Selected: {{filename}}"
+      },
+      "fontSize": "Font Size",
+      "position": "Position",
+      "rotation": "Rotation (degrees)",
+      "opacity": "Opacity (%)",
+      "spacing": {
+        "width": "Width Spacing",
+        "height": "Height Spacing"
+      }
+    },
+    "positions": {
+      "topLeft": "Top Left",
+      "topCenter": "Top Center", 
+      "topRight": "Top Right",
+      "centerLeft": "Center Left",
+      "center": "Center",
+      "centerRight": "Center Right",
+      "bottomLeft": "Bottom Left",
+      "bottomCenter": "Bottom Center",
+      "bottomRight": "Bottom Right"
+    }
   }
 }
diff --git a/frontend/src/components/tools/addWatermark/AddWatermarkSettings.tsx b/frontend/src/components/tools/addWatermark/AddWatermarkSettings.tsx
new file mode 100644
index 000000000..3dcc63bfe
--- /dev/null
+++ b/frontend/src/components/tools/addWatermark/AddWatermarkSettings.tsx
@@ -0,0 +1,174 @@
+import React, { useRef } from "react";
+import { Button, Stack, Text, NumberInput, Select, TextInput, FileButton } from "@mantine/core";
+import { useTranslation } from "react-i18next";
+
+interface AddWatermarkParameters {
+  watermarkType: 'text' | 'image';
+  watermarkText: string;
+  watermarkImage?: File;
+  fontSize: number;
+  rotation: number;
+  opacity: number;
+  widthSpacer: number;
+  heightSpacer: number;
+  position: string;
+  overrideX?: number;
+  overrideY?: number;
+}
+
+interface AddWatermarkSettingsProps {
+  parameters: AddWatermarkParameters;
+  onParameterChange: (key: keyof AddWatermarkParameters, value: any) => void;
+  disabled?: boolean;
+}
+
+const AddWatermarkSettings = ({ parameters, onParameterChange, disabled = false }: AddWatermarkSettingsProps) => {
+  const { t } = useTranslation();
+  const resetRef = useRef<() => void>(null);
+
+  const positionOptions = [
+    { value: 'topLeft', label: 'Top Left' },
+    { value: 'topCenter', label: 'Top Center' },
+    { value: 'topRight', label: 'Top Right' },
+    { value: 'centerLeft', label: 'Center Left' },
+    { value: 'center', label: 'Center' },
+    { value: 'centerRight', label: 'Center Right' },
+    { value: 'bottomLeft', label: 'Bottom Left' },
+    { value: 'bottomCenter', label: 'Bottom Center' },
+    { value: 'bottomRight', label: 'Bottom Right' }
+  ];
+
+  return (
+    <Stack gap="md">
+      {/* Watermark Type Selection */}
+      <Stack gap="sm">
+        <Text size="sm" fw={500}>Watermark Type</Text>
+        <div style={{ display: 'flex', gap: '4px' }}>
+          <Button
+            variant={parameters.watermarkType === 'text' ? 'filled' : 'outline'}
+            color={parameters.watermarkType === 'text' ? 'blue' : 'gray'}
+            onClick={() => onParameterChange('watermarkType', 'text')}
+            disabled={disabled}
+            style={{ flex: 1, height: 'auto', minHeight: '40px', fontSize: '11px' }}
+          >
+            <div style={{ textAlign: 'center', lineHeight: '1.1', fontSize: '11px' }}>
+              Text
+            </div>
+          </Button>
+          <Button
+            variant={parameters.watermarkType === 'image' ? 'filled' : 'outline'}
+            color={parameters.watermarkType === 'image' ? 'blue' : 'gray'}
+            onClick={() => onParameterChange('watermarkType', 'image')}
+            disabled={disabled}
+            style={{ flex: 1, height: 'auto', minHeight: '40px', fontSize: '11px' }}
+          >
+            <div style={{ textAlign: 'center', lineHeight: '1.1', fontSize: '11px' }}>
+              Image
+            </div>
+          </Button>
+        </div>
+      </Stack>
+
+      {/* Text Watermark Settings */}
+      {parameters.watermarkType === 'text' && (
+        <Stack gap="sm">
+          <Text size="sm" fw={500}>Watermark Text</Text>
+          <TextInput
+            placeholder="Enter watermark text"
+            value={parameters.watermarkText}
+            onChange={(e) => onParameterChange('watermarkText', e.target.value)}
+            disabled={disabled}
+          />
+          
+          <Text size="sm" fw={500}>Font Size</Text>
+          <NumberInput
+            value={parameters.fontSize}
+            onChange={(value) => onParameterChange('fontSize', value || 12)}
+            min={8}
+            max={72}
+            disabled={disabled}
+          />
+        </Stack>
+      )}
+
+      {/* Image Watermark Settings */}
+      {parameters.watermarkType === 'image' && (
+        <Stack gap="sm">
+          <Text size="sm" fw={500}>Watermark Image</Text>
+          <FileButton
+            resetRef={resetRef}
+            onChange={(file) => onParameterChange('watermarkImage', file)}
+            accept="image/*"
+            disabled={disabled}
+          >
+            {(props) => (
+              <Button {...props} variant="outline" fullWidth>
+                {parameters.watermarkImage ? parameters.watermarkImage.name : 'Choose Image'}
+              </Button>
+            )}
+          </FileButton>
+          {parameters.watermarkImage && (
+            <Text size="xs" c="dimmed">
+              Selected: {parameters.watermarkImage.name}
+            </Text>
+          )}
+        </Stack>
+      )}
+
+      {/* Position Settings */}
+      <Stack gap="sm">
+        <Text size="sm" fw={500}>Position</Text>
+        <Select
+          value={parameters.position}
+          onChange={(value) => value && onParameterChange('position', value)}
+          data={positionOptions}
+          disabled={disabled}
+        />
+      </Stack>
+
+      {/* Appearance Settings */}
+      <Stack gap="sm">
+        <Text size="sm" fw={500}>Rotation (degrees)</Text>
+        <NumberInput
+          value={parameters.rotation}
+          onChange={(value) => onParameterChange('rotation', value || 0)}
+          min={-360}
+          max={360}
+          disabled={disabled}
+        />
+
+        <Text size="sm" fw={500}>Opacity (%)</Text>
+        <NumberInput
+          value={parameters.opacity}
+          onChange={(value) => onParameterChange('opacity', value || 50)}
+          min={0}
+          max={100}
+          disabled={disabled}
+        />
+      </Stack>
+
+      {/* Spacing Settings */}
+      <Stack gap="sm">
+        <Text size="sm" fw={500}>Width Spacing</Text>
+        <NumberInput
+          value={parameters.widthSpacer}
+          onChange={(value) => onParameterChange('widthSpacer', value || 50)}
+          min={0}
+          max={200}
+          disabled={disabled}
+        />
+
+        <Text size="sm" fw={500}>Height Spacing</Text>
+        <NumberInput
+          value={parameters.heightSpacer}
+          onChange={(value) => onParameterChange('heightSpacer', value || 50)}
+          min={0}
+          max={200}
+          disabled={disabled}
+        />
+      </Stack>
+    </Stack>
+  );
+};
+
+export default AddWatermarkSettings;
\ No newline at end of file
diff --git a/frontend/src/hooks/tools/addWatermark/useAddWatermarkOperation.ts b/frontend/src/hooks/tools/addWatermark/useAddWatermarkOperation.ts
new file mode 100644
index 000000000..9251d91d5
--- /dev/null
+++ b/frontend/src/hooks/tools/addWatermark/useAddWatermarkOperation.ts
@@ -0,0 +1,44 @@
+import { useTranslation } from 'react-i18next';
+import { useToolOperation } from '../shared/useToolOperation';
+import { createStandardErrorHandler } from '../../../utils/toolErrorHandler';
+import { AddWatermarkParameters } from './useAddWatermarkParameters';
+
+const buildFormData = (parameters: AddWatermarkParameters, file: File): FormData => {
+  const formData = new FormData();
+  formData.append("fileInput", file);
+
+  if (parameters.watermarkType === 'text') {
+    formData.append("watermarkText", parameters.watermarkText);
+  } else if (parameters.watermarkImage) {
+    formData.append("watermarkImage", parameters.watermarkImage);
+  }
+
+  formData.append("fontSize", parameters.fontSize.toString());
+  formData.append("rotation", parameters.rotation.toString());
+  formData.append("opacity", (parameters.opacity / 100).toString()); // Convert percentage to decimal
+  formData.append("widthSpacer", parameters.widthSpacer.toString());
+  formData.append("heightSpacer", parameters.heightSpacer.toString());
+  formData.append("position", parameters.position);
+
+  if (parameters.overrideX !== undefined) {
+    formData.append("overrideX", parameters.overrideX.toString());
+  }
+  if (parameters.overrideY !== undefined) {
+    formData.append("overrideY", parameters.overrideY.toString());
+  }
+
+  return formData;
+};
+
+export const useAddWatermarkOperation = () => {
+  const { t } = useTranslation();
+
+  return useToolOperation<AddWatermarkParameters>({
+    operationType: 'watermark',
+    endpoint: '/api/v1/security/add-watermark',
+    buildFormData,
+    filePrefix: t('watermark.filenamePrefix', 'watermarked') + '_',
+    multiFileEndpoint: false, // Individual API calls per file
+    getErrorMessage: createStandardErrorHandler(t('watermark.error.failed', 'An error occurred while adding watermark to the PDF.'))
+  });
+};
\ No newline at end of file
diff --git a/frontend/src/hooks/tools/addWatermark/useAddWatermarkParameters.ts b/frontend/src/hooks/tools/addWatermark/useAddWatermarkParameters.ts
new file mode 100644
index 000000000..4f3405221
--- /dev/null
+++ b/frontend/src/hooks/tools/addWatermark/useAddWatermarkParameters.ts
@@ -0,0 +1,56 @@
+import { useState, useCallback } from 'react';
+
+export interface AddWatermarkParameters {
+  watermarkType: 'text' | 'image';
+  watermarkText: string;
+  watermarkImage?: File;
+  fontSize: number;
+  rotation: number;
+  opacity: number;
+  widthSpacer: number;
+  heightSpacer: number;
+  position: string;
+  overrideX?: number;
+  overrideY?: number;
+}
+
+const defaultParameters: AddWatermarkParameters = {
+  watermarkType: 'text',
+  watermarkText: '',
+  fontSize: 12,
+  rotation: 0,
+  opacity: 50,
+  widthSpacer: 50,
+  heightSpacer: 50,
+  position: 'center'
+};
+
+export const useAddWatermarkParameters = () => {
+  const [parameters, setParameters] = useState<AddWatermarkParameters>(defaultParameters);
+
+  const updateParameter = useCallback(<K extends keyof AddWatermarkParameters>(
+    key: K,
+    value: AddWatermarkParameters[K]
+  ) => {
+    setParameters(prev => ({ ...prev, [key]: value }));
+  }, []);
+
+  const resetParameters = useCallback(() => {
+    setParameters(defaultParameters);
+  }, []);
+
+  const validateParameters = useCallback((): boolean => {
+    if (parameters.watermarkType === 'text') {
+      return parameters.watermarkText.trim().length > 0;
+    } else {
+      return parameters.watermarkImage !== undefined;
+    }
+  }, [parameters]);
+
+  return {
+    parameters,
+    updateParameter,
+    resetParameters,
+    validateParameters
+  };
+};
\ No newline at end of file
diff --git a/frontend/src/hooks/useToolManagement.tsx b/frontend/src/hooks/useToolManagement.tsx
index aac9c5421..7c7dfb947 100644
--- a/frontend/src/hooks/useToolManagement.tsx
+++ b/frontend/src/hooks/useToolManagement.tsx
@@ -6,6 +6,7 @@ import SwapHorizIcon from "@mui/icons-material/SwapHoriz";
 import ApiIcon from "@mui/icons-material/Api";
 import CleaningServicesIcon from "@mui/icons-material/CleaningServices";
 import LockIcon from "@mui/icons-material/Lock";
+import BrandingWatermarkIcon from "@mui/icons-material/BrandingWatermark";
 import { useMultipleEndpointsEnabled } from "./useEndpointConfig";
 import { Tool, ToolDefinition, BaseToolProps, ToolRegistry } from "../types/tool";
 
@@ -104,6 +105,15 @@ const toolDefinitions: Record<string, ToolDefinition> = {
     description: "Change document restrictions and permissions",
     endpoints: ["add-password"]
   },
+  watermark: {
+    id: "watermark",
+    icon: <BrandingWatermarkIcon />,
+    component: React.lazy(() => import("../tools/AddWatermark")),
+    maxFiles: -1,
+    category: "security",
+    description: "Add text or image watermarks to PDF files",
+    endpoints: ["add-watermark"]
+  },
 
 };
 
diff --git a/frontend/src/tools/AddWatermark.tsx b/frontend/src/tools/AddWatermark.tsx
new file mode 100644
index 000000000..dc549745d
--- /dev/null
+++ b/frontend/src/tools/AddWatermark.tsx
@@ -0,0 +1,167 @@
+import React, { useEffect, useMemo } from "react";
+import { Button, Stack, Text } from "@mantine/core";
+import { useTranslation } from "react-i18next";
+import DownloadIcon from "@mui/icons-material/Download";
+import { useEndpointEnabled } from "../hooks/useEndpointConfig";
+import { useFileContext } from "../contexts/FileContext";
+import { useToolFileSelection } from "../contexts/FileSelectionContext";
+
+import ToolStep, { ToolStepContainer } from "../components/tools/shared/ToolStep";
+import OperationButton from "../components/tools/shared/OperationButton";
+import ErrorNotification from "../components/tools/shared/ErrorNotification";
+import FileStatusIndicator from "../components/tools/shared/FileStatusIndicator";
+import ResultsPreview from "../components/tools/shared/ResultsPreview";
+
+import AddWatermarkSettings from "../components/tools/addWatermark/AddWatermarkSettings";
+
+import { useAddWatermarkParameters } from "../hooks/tools/addWatermark/useAddWatermarkParameters";
+import { useAddWatermarkOperation } from "../hooks/tools/addWatermark/useAddWatermarkOperation";
+import { BaseToolProps } from "../types/tool";
+
+const AddWatermark = ({ onPreviewFile, onComplete, onError }: BaseToolProps) => {
+  const { t } = useTranslation();
+  const { setCurrentMode } = useFileContext();
+  const { selectedFiles } = useToolFileSelection();
+
+  const watermarkParams = useAddWatermarkParameters();
+  const watermarkOperation = useAddWatermarkOperation();
+
+  // Endpoint validation
+  const { enabled: endpointEnabled, loading: endpointLoading } = useEndpointEnabled("add-watermark");
+
+  useEffect(() => {
+    watermarkOperation.resetResults();
+    onPreviewFile?.(null);
+  }, [watermarkParams.parameters, selectedFiles]);
+
+  const handleAddWatermark = async () => {
+    try {
+      await watermarkOperation.executeOperation(
+        watermarkParams.parameters,
+        selectedFiles
+      );
+      if (watermarkOperation.files && onComplete) {
+        onComplete(watermarkOperation.files);
+      }
+    } catch (error) {
+      if (onError) {
+        onError(error instanceof Error ? error.message : 'Add watermark operation failed');
+      }
+    }
+  };
+
+  const handleThumbnailClick = (file: File) => {
+    onPreviewFile?.(file);
+    sessionStorage.setItem('previousMode', 'watermark');
+    setCurrentMode('viewer');
+  };
+
+  const handleSettingsReset = () => {
+    watermarkOperation.resetResults();
+    onPreviewFile?.(null);
+    setCurrentMode('watermark');
+  };
+
+  const hasFiles = selectedFiles.length > 0;
+  const hasResults = watermarkOperation.files.length > 0 || watermarkOperation.downloadUrl !== null;
+  const filesCollapsed = hasFiles;
+  const settingsCollapsed = hasResults;
+
+  const previewResults = useMemo(() =>
+    watermarkOperation.files?.map((file, index) => ({
+      file,
+      thumbnail: watermarkOperation.thumbnails[index]
+    })) || [],
+    [watermarkOperation.files, watermarkOperation.thumbnails]
+  );
+
+  return (
+    <ToolStepContainer>
+      <Stack gap="sm" h="100%" p="sm" style={{ overflow: 'auto' }}>
+        {/* Files Step */}
+        <ToolStep
+          title="Files"
+          isVisible={true}
+          isCollapsed={filesCollapsed}
+          isCompleted={filesCollapsed}
+          completedMessage={hasFiles ?
+            selectedFiles.length === 1
+              ? `Selected: ${selectedFiles[0].name}`
+              : `Selected: ${selectedFiles.length} files`
+            : undefined}
+        >
+          <FileStatusIndicator
+            selectedFiles={selectedFiles}
+            placeholder="Select a PDF file in the main view to get started"
+          />
+        </ToolStep>
+
+        {/* Settings Step */}
+        <ToolStep
+          title="Settings"
+          isVisible={hasFiles}
+          isCollapsed={settingsCollapsed}
+          isCompleted={settingsCollapsed}
+          onCollapsedClick={settingsCollapsed ? handleSettingsReset : undefined}
+          completedMessage={settingsCollapsed ? "Watermark added" : undefined}
+        >
+          <Stack gap="sm">
+            <AddWatermarkSettings
+              parameters={watermarkParams.parameters}
+              onParameterChange={watermarkParams.updateParameter}
+              disabled={endpointLoading}
+            />
+
+            <OperationButton
+              onClick={handleAddWatermark}
+              isLoading={watermarkOperation.isLoading}
+              disabled={!watermarkParams.validateParameters() || !hasFiles || !endpointEnabled}
+              loadingText={t("loading")}
+              submitText="Add Watermark and Review"
+            />
+          </Stack>
+        </ToolStep>
+
+        {/* Results Step */}
+        <ToolStep
+          title="Results"
+          isVisible={hasResults}
+        >
+          <Stack gap="sm">
+            {watermarkOperation.status && (
+              <Text size="sm" c="dimmed">{watermarkOperation.status}</Text>
+            )}
+
+            <ErrorNotification
+              error={watermarkOperation.errorMessage}
+              onClose={watermarkOperation.clearError}
+            />
+
+            {watermarkOperation.downloadUrl && (
+              <Button
+                component="a"
+                href={watermarkOperation.downloadUrl}
+                download={watermarkOperation.downloadFilename}
+                leftSection={<DownloadIcon />}
+                color="green"
+                fullWidth
+                mb="md"
+              >
+                {t("download", "Download")}
+              </Button>
+            )}
+
+            <ResultsPreview
+              files={previewResults}
+              onFileClick={handleThumbnailClick}
+              isGeneratingThumbnails={watermarkOperation.isGeneratingThumbnails}
+              title="Watermark Results"
+            />
+          </Stack>
+        </ToolStep>
+      </Stack>
+    </ToolStepContainer>
+  );
+}
+
+export default AddWatermark;
\ No newline at end of file
diff --git a/frontend/src/types/fileContext.ts b/frontend/src/types/fileContext.ts
index dec7b03a1..a17b48f3c 100644
--- a/frontend/src/types/fileContext.ts
+++ b/frontend/src/types/fileContext.ts
@@ -16,7 +16,8 @@ export type ModeType =
   | 'convert' 
   | 'sanitize'
   | 'addPassword'
-  | 'changePermissions';
+  | 'changePermissions'
+  | 'watermark';
 
 export type ViewType = 'viewer' | 'pageEditor' | 'fileEditor';