diff --git a/frontend/src/components/FileIntegrityDisplay.tsx b/frontend/src/components/FileIntegrityDisplay.tsx
index e432ccf..23315e0 100644
--- a/frontend/src/components/FileIntegrityDisplay.tsx
+++ b/frontend/src/components/FileIntegrityDisplay.tsx
@@ -30,6 +30,7 @@ interface FileIntegrityDisplayProps {
   createdAt: string;
   updatedAt: string;
   userId?: string;
+  username?: string;
   compact?: boolean;
 }
 
@@ -41,6 +42,7 @@ const FileIntegrityDisplay: React.FC<FileIntegrityDisplayProps> = ({
   createdAt,
   updatedAt,
   userId,
+  username,
   compact = false,
 }) => {
   const [copied, setCopied] = useState(false);
@@ -328,7 +330,7 @@ const FileIntegrityDisplay: React.FC<FileIntegrityDisplayProps> = ({
               Uploaded By
             </Typography>
             <Chip 
-              label={`User: ${userId ? userId.substring(0, 8) + '...' : 'Unknown'}`} 
+              label={username || (userId ? `User: ${userId.substring(0, 8)}...` : 'Unknown')} 
               size="small"
               sx={{ 
                 fontSize: '0.75rem',
diff --git a/frontend/src/components/ProcessingTimeline.tsx b/frontend/src/components/ProcessingTimeline.tsx
index 81cd457..6c025f0 100644
--- a/frontend/src/components/ProcessingTimeline.tsx
+++ b/frontend/src/components/ProcessingTimeline.tsx
@@ -39,6 +39,7 @@ interface ProcessingTimelineProps {
   createdAt: string;
   updatedAt: string;
   userId: string;
+  username?: string;
   ocrStatus?: string;
   ocrCompletedAt?: string;
   ocrRetryCount?: number;
@@ -62,6 +63,7 @@ const ProcessingTimeline: React.FC<ProcessingTimelineProps> = ({
   createdAt,
   updatedAt,
   userId,
+  username,
   ocrStatus,
   ocrCompletedAt,
   ocrRetryCount = 0,
@@ -114,7 +116,7 @@ const ProcessingTimeline: React.FC<ProcessingTimelineProps> = ({
       title: 'Document Uploaded',
       description: `File "${fileName}" was uploaded successfully`,
       status: 'success',
-      metadata: { userId },
+      metadata: { userId, username },
     });
 
     // OCR processing events
@@ -352,7 +354,7 @@ const ProcessingTimeline: React.FC<ProcessingTimelineProps> = ({
                 <Box sx={{ display: 'flex', alignItems: 'center', mt: 1 }}>
                   <PersonIcon sx={{ fontSize: 14, mr: 0.5, color: theme.palette.text.secondary }} />
                   <Typography variant="caption" color="text.secondary">
-                    User: {event.metadata.userId.substring(0, 8)}...
+                    {event.metadata.username || `User: ${event.metadata.userId.substring(0, 8)}...`}
                   </Typography>
                 </Box>
               )}
diff --git a/frontend/src/pages/DocumentDetailsPage.tsx b/frontend/src/pages/DocumentDetailsPage.tsx
index cefc0fa..9805315 100644
--- a/frontend/src/pages/DocumentDetailsPage.tsx
+++ b/frontend/src/pages/DocumentDetailsPage.tsx
@@ -699,6 +699,7 @@ const DocumentDetailsPage: React.FC = () => {
                 createdAt={document.created_at}
                 updatedAt={document.updated_at}
                 userId={document.user_id}
+                username={document.username}
                 />
               </Box>
             </Grid>
@@ -884,6 +885,7 @@ const DocumentDetailsPage: React.FC = () => {
                   createdAt={document.created_at}
                   updatedAt={document.updated_at}
                   userId={document.user_id}
+                  username={document.username}
                   ocrStatus={document.has_ocr_text ? 'completed' : 'pending'}
                   ocrCompletedAt={ocrData?.ocr_completed_at}
                   ocrError={ocrData?.ocr_error}
diff --git a/frontend/src/services/api.ts b/frontend/src/services/api.ts
index 5f4f1a5..1b44707 100644
--- a/frontend/src/services/api.ts
+++ b/frontend/src/services/api.ts
@@ -21,6 +21,7 @@ export interface Document {
   created_at: string
   updated_at: string
   user_id: string
+  username?: string
   file_hash?: string
   original_created_at?: string
   original_modified_at?: string
diff --git a/src/models/responses.rs b/src/models/responses.rs
index e3b6f49..66e00e6 100644
--- a/src/models/responses.rs
+++ b/src/models/responses.rs
@@ -51,6 +51,9 @@ pub struct DocumentResponse {
     pub updated_at: DateTime<Utc>,
     /// User who uploaded/owns the document
     pub user_id: Uuid,
+    /// Username of the user who uploaded/owns the document
+    #[serde(skip_serializing_if = "Option::is_none", default)]
+    pub username: Option<String>,
     /// SHA256 hash of the file content
     #[serde(skip_serializing_if = "Option::is_none", default)]
     pub file_hash: Option<String>,
@@ -271,6 +274,7 @@ impl From<Document> for DocumentResponse {
             created_at: doc.created_at,
             updated_at: doc.updated_at,
             user_id: doc.user_id,
+            username: None, // Username will be populated separately where needed
             file_hash: doc.file_hash,
             has_ocr_text: doc.ocr_text.is_some(),
             ocr_confidence: doc.ocr_confidence,
diff --git a/src/routes/documents/crud.rs b/src/routes/documents/crud.rs
index 1f33b69..d4b2774 100644
--- a/src/routes/documents/crud.rs
+++ b/src/routes/documents/crud.rs
@@ -189,8 +189,20 @@ pub async fn get_document_by_id(
             StatusCode::INTERNAL_SERVER_ERROR
         })?;
 
+    // Get username for the document owner
+    let username = state
+        .db
+        .get_user_by_id(document.user_id)
+        .await
+        .map_err(|e| {
+            error!("Failed to get user for document {}: {}", document_id, e);
+            StatusCode::INTERNAL_SERVER_ERROR
+        })?
+        .map(|user| user.username);
+
     let mut response = DocumentResponse::from(document);
     response.labels = labels;
+    response.username = username;
 
     Ok(Json(response))
 }