diff --git a/README.md b/README.md
index 2067ca5..db7e9e6 100644
--- a/README.md
+++ b/README.md
@@ -137,7 +137,12 @@ npm run dev
 - ✅ **Multi-Notebook Management** - Organize documents into collections
 - ✅ **6 AI Models** - GPT-5, Claude 4.5, Gemini 2.5 Pro, GPT-4o, Gemini Flash, GPT-4
 - ✅ **Pricing Display** - See costs for each model
-- ✅ **Multi-Document Upload** - Upload 1-20 PDFs per notebook
+- ✅ **Multi-Document Upload** - Upload 1-20 files per notebook
+  - Documents: PDF, Word, PowerPoint, RTF, EPUB, Pages, Keynote, TXT, MD
+  - Spreadsheets: Excel, CSV, TSV, Numbers
+  - Images: JPG, PNG, GIF, BMP, TIFF, SVG (with OCR)
+  - Audio: MP3, WAV, M4A (transcription, 20MB limit)
+  - Web: HTML
 - ✅ **Background Processing** - Non-blocking document analysis
 - ✅ **Real-time Status** - Watch processing progress
 
@@ -311,11 +316,16 @@ UPDATE users SET is_admin = true WHERE email = 'your@email.com';
 
 **Upload Documents:**
 1. Open your notebook
-2. Click "Select PDF Files"
-3. Choose 1-20 PDFs
+2. Click "Select Files"
+3. Choose 1-20 files (supports 30+ formats):
+   - Documents: PDF, DOCX, PPTX, RTF, EPUB, TXT, MD, and more
+   - Spreadsheets: XLSX, CSV, TSV
+   - Images: JPG, PNG (with OCR)
+   - Audio: MP3, WAV (with transcription, 20MB limit)
+   - Web: HTML
 4. Click "Upload X File(s)"
-5. Wait ~1 minute per document for processing
-6. Expand documents to see summaries, highlights, Q&A
+5. Wait ~1 minute per file for processing
+6. Expand files to see summaries, highlights, Q&A
 
 **Generate Cross-Document Analysis:**
 1. Click "Cross-Doc Analysis" button
@@ -562,7 +572,7 @@ curl -X PUT "http://localhost:9000/api/admin/users/USER_ID/role?is_admin=true&re
 - **Role-Based Access:** Admin-only pages
 - **CORS:** Configured for localhost:4000
 - **SQL Injection Protection:** SQLAlchemy ORM
-- **File Validation:** PDF-only uploads
+- **File Validation:** 30+ file types supported (documents, spreadsheets, images, audio, web)
 - **Permission System:** Granular notebook sharing
 
 ---
diff --git a/backend/src/api/routes/documents.py b/backend/src/api/routes/documents.py
index 63576d4..ea11454 100644
--- a/backend/src/api/routes/documents.py
+++ b/backend/src/api/routes/documents.py
@@ -52,10 +52,22 @@ async def upload_document(
     if not notebook:
         raise HTTPException(status_code=404, detail="Notebook not found")
 
-    # Validate file type
-    supported_extensions = ('.pdf', '.docx', '.doc', '.pptx', '.ppt', '.txt', '.md')
+    # Validate file type - LlamaParse supports all these formats
+    supported_extensions = (
+        # Documents
+        '.pdf', '.docx', '.doc', '.pptx', '.ppt', '.txt', '.md', '.rtf', '.epub',
+        '.pages', '.key', '.odt', '.odp',
+        # Spreadsheets
+        '.xlsx', '.xls', '.xlsm', '.xlsb', '.csv', '.tsv', '.numbers', '.ods',
+        # Images (OCR)
+        '.jpg', '.jpeg', '.png', '.gif', '.bmp', '.tiff', '.webp', '.svg',
+        # Web
+        '.html', '.htm',
+        # Audio (transcription, 20MB limit)
+        '.mp3', '.mp4', '.mpeg', '.m4a', '.wav', '.webm'
+    )
     if not file.filename.lower().endswith(supported_extensions):
-        raise HTTPException(status_code=400, detail="Supported file types: PDF, DOCX, DOC, PPTX, PPT, TXT, MD")
+        raise HTTPException(status_code=400, detail="Unsupported file type. See upload page for supported formats.")
 
     try:
         # Save to temporary file
diff --git a/frontend/src/app/notebooks/[id]/page.tsx b/frontend/src/app/notebooks/[id]/page.tsx
index d9570b3..a16d6a9 100644
--- a/frontend/src/app/notebooks/[id]/page.tsx
+++ b/frontend/src/app/notebooks/[id]/page.tsx
@@ -167,14 +167,26 @@ export default function NotebookDetailPage() {
     const files = e.target.files;
     if (!files) return;
 
-    const supportedExtensions = ['.pdf', '.docx', '.doc', '.pptx', '.ppt', '.txt', '.md'];
+    const supportedExtensions = [
+      // Documents
+      '.pdf', '.docx', '.doc', '.pptx', '.ppt', '.txt', '.md', '.rtf', '.epub',
+      '.pages', '.key', '.odt', '.odp',
+      // Spreadsheets
+      '.xlsx', '.xls', '.xlsm', '.xlsb', '.csv', '.tsv', '.numbers', '.ods',
+      // Images (OCR)
+      '.jpg', '.jpeg', '.png', '.gif', '.bmp', '.tiff', '.webp', '.svg',
+      // Web
+      '.html', '.htm',
+      // Audio (transcription)
+      '.mp3', '.mp4', '.mpeg', '.m4a', '.wav', '.webm'
+    ];
     const validFiles = Array.from(files).filter(file => {
       const fileName = file.name.toLowerCase();
       return supportedExtensions.some(ext => fileName.endsWith(ext));
     });
 
     if (validFiles.length !== files.length) {
-      alert('Supported file types: PDF, DOCX, DOC, PPTX, PPT, TXT, MD');
+      alert('Unsupported file type(s) detected.\n\nSupported formats:\n• Documents: PDF, DOCX, PPTX, RTF, EPUB, Pages, Keynote, TXT, MD\n• Spreadsheets: XLSX, XLS, CSV, TSV, Numbers\n• Images: JPG, PNG, GIF, BMP, TIFF, SVG (with OCR)\n• Web: HTML\n• Audio: MP3, WAV, M4A (transcription, 20MB limit)');
     }
 
     if (validFiles.length > 20) {
@@ -537,13 +549,16 @@ export default function NotebookDetailPage() {
           <div className="border-2 border-dashed border-gray-300 rounded-lg p-8 hover:border-blue-400 transition">
             <Upload className="w-12 h-12 text-gray-700 mx-auto mb-4" />
             <p className="text-center text-gray-700 mb-4">
-              Upload documents: PDF, DOCX, PPTX, TXT, MD (up to 20 files)
+              Upload documents, spreadsheets, images, audio, or web pages (up to 20 files)
+            </p>
+            <p className="text-xs text-gray-700 text-center mb-4">
+              Supports: PDF, Office (Word/Excel/PowerPoint), Images (JPG/PNG), Audio (MP3/WAV), CSV, HTML, and more
             </p>
 
             <input
               ref={fileInputRef}
               type="file"
-              accept=".pdf,.docx,.doc,.pptx,.ppt,.txt,.md"
+              accept=".pdf,.docx,.doc,.pptx,.ppt,.xlsx,.xls,.xlsm,.xlsb,.csv,.tsv,.txt,.md,.rtf,.epub,.pages,.key,.odt,.odp,.numbers,.ods,.jpg,.jpeg,.png,.gif,.bmp,.tiff,.webp,.svg,.html,.htm,.mp3,.mp4,.mpeg,.m4a,.wav,.webm"
               multiple
               onChange={handleFilesSelect}
               className="hidden"