diff --git a/README.md b/README.md
index d29bf7c..deb8554 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ One Docker container. OTLP ingest on `:4318`, interactive analytics dashboard on
 ## What you get
 
 - **Overview dashboard** — KPI cards for sessions, unique users, total cost, and token counts (30-day window), with per-user filter across all charts
-- **Sessions** — live table of every Claude Code session with model, duration, cost, and status (OK / ERROR)
+- **Sessions** — live table of every Claude Code session with user, model, duration, cost, and status (OK / ERROR); search by user and click any user to filter the table to their sessions
 - **History** — time-series and daily-activity heatmaps for sessions and token spend over time
 - **Costs** — cumulative spend chart + breakdown table by model
 - **Tools** — call counts, average duration, and error rate per tool (`Bash`, `Read`, `Edit`, …)
diff --git a/frontend/src/api/index.ts b/frontend/src/api/index.ts
index 6c3fcdb..36b52e7 100644
--- a/frontend/src/api/index.ts
+++ b/frontend/src/api/index.ts
@@ -20,6 +20,7 @@ export interface OverviewResponse {
 
 export interface SessionItem {
   session_id: string
+  user_id: string
   first_seen: string
   last_seen: string
   model: string
diff --git a/frontend/src/pages/Sessions.module.css b/frontend/src/pages/Sessions.module.css
index d61acc4..19ffdbc 100644
--- a/frontend/src/pages/Sessions.module.css
+++ b/frontend/src/pages/Sessions.module.css
@@ -85,6 +85,26 @@
   color: var(--color-accent);
 }
 
+.userLink {
+  background: none;
+  border: none;
+  padding: 0;
+  margin: 0;
+  cursor: pointer;
+  color: var(--color-accent);
+  font: inherit;
+  text-align: left;
+}
+
+.userLink:hover {
+  text-decoration: underline;
+}
+
+.anonUser {
+  color: var(--color-text-2);
+  font-style: italic;
+}
+
 .pagination {
   display: flex;
   align-items: center;
diff --git a/frontend/src/pages/Sessions.tsx b/frontend/src/pages/Sessions.tsx
index 8f5d6a0..191f789 100644
--- a/frontend/src/pages/Sessions.tsx
+++ b/frontend/src/pages/Sessions.tsx
@@ -22,11 +22,21 @@ export default function Sessions() {
     })
   }
 
+  function applyUserFilter(uid: string) {
+    setSearchParams((prev) => {
+      const next = new URLSearchParams(prev)
+      next.set('user_id', uid)
+      return next
+    })
+    setPage(1)
+  }
+
   const filtered = useMemo(() => {
     if (!data) return []
+    const needle = search.toLowerCase()
     return data.items.filter(
       (s) =>
-        (search === '' || s.session_id.toLowerCase().includes(search.toLowerCase())) &&
+        (search === '' || (s.user_id ?? '').toLowerCase().includes(needle)) &&
         (statusFilter === 'all' || s.status === statusFilter),
     )
   }, [data, search, statusFilter])
@@ -47,7 +57,7 @@ export default function Sessions() {
       <div className={styles.filterBar}>
         <input
           className={styles.searchInput}
-          placeholder="Search by session ID…"
+          placeholder="Search by user…"
           value={search}
           onChange={(e) => { setSearch(e.target.value); setPage(1) }}
         />
@@ -88,6 +98,23 @@ export default function Sessions() {
                   </Link>
                 ),
               },
+              {
+                key: 'user_id',
+                label: 'User',
+                sortable: true,
+                render: (v) =>
+                  v ? (
+                    <button
+                      className={styles.userLink}
+                      onClick={(e) => { e.stopPropagation(); applyUserFilter(String(v)) }}
+                      title={`Filter by ${v}`}
+                    >
+                      {String(v)}
+                    </button>
+                  ) : (
+                    <span className={styles.anonUser}>anonymous</span>
+                  ),
+              },
               {
                 key: 'first_seen',
                 label: 'Started',
diff --git a/internal/api/handler.go b/internal/api/handler.go
index d4bbd4b..89eca7a 100644
--- a/internal/api/handler.go
+++ b/internal/api/handler.go
@@ -309,6 +309,7 @@ func (h *Handler) handleOverview(w http.ResponseWriter, r *http.Request) {
 
 type sessionItem struct {
 	SessionID    string  `json:"session_id"`
+	UserID       string  `json:"user_id"`
 	FirstSeen    string  `json:"first_seen"`
 	LastSeen     string  `json:"last_seen"`
 	Model        string  `json:"model"`
@@ -368,7 +369,8 @@ func (h *Handler) handleSessions(w http.ResponseWriter, r *http.Request) {
 			COALESCE(SUM(input_tokens), 0),
 			COALESCE(SUM(output_tokens), 0),
 			COUNT(*) FILTER (WHERE tool_name IS NOT NULL AND tool_name <> ''),
-			MAX(CASE WHEN status_code = 2 THEN 1 ELSE 0 END)
+			MAX(CASE WHEN status_code = 2 THEN 1 ELSE 0 END),
+			COALESCE(MAX(user_id), '')
 		FROM spans
 		WHERE session_id IS NOT NULL%s
 		GROUP BY session_id
@@ -394,7 +396,7 @@ func (h *Handler) handleSessions(w http.ResponseWriter, r *http.Request) {
 		var firstSeen, lastSeen time.Time
 		var hasError int
 		if err := rows.Scan(&s.SessionID, &firstSeen, &lastSeen, &s.Model,
-			&s.CostUSD, &s.InputTokens, &s.OutputTokens, &s.ToolCalls, &hasError); err != nil {
+			&s.CostUSD, &s.InputTokens, &s.OutputTokens, &s.ToolCalls, &hasError, &s.UserID); err != nil {
 			continue
 		}
 		s.FirstSeen = firstSeen.UTC().Format(time.RFC3339)
diff --git a/internal/api/handler_test.go b/internal/api/handler_test.go
index 71d4936..4628a74 100644
--- a/internal/api/handler_test.go
+++ b/internal/api/handler_test.go
@@ -241,6 +241,28 @@ func TestSessions(t *testing.T) {
 				}
 			},
 		},
+		{
+			name: "surfaces user_id",
+			seed: func(t *testing.T, db *storage.DB) {
+				now := time.Now()
+				insertSpan(t, db, storage.Span{
+					TraceID: "t1", SpanID: "s1", Name: "llm", SessionID: "sess1",
+					UserID: "alice", StartTime: now, EndTime: now.Add(time.Second),
+				})
+			},
+			path:       "/api/v1/sessions",
+			wantStatus: http.StatusOK,
+			checkBody: func(t *testing.T, body map[string]any) {
+				items, ok := body["items"].([]any)
+				if !ok || len(items) != 1 {
+					t.Fatalf("want 1 item, got %v", body["items"])
+				}
+				item := items[0].(map[string]any)
+				if item["user_id"] != "alice" {
+					t.Errorf("want user_id=alice, got %v", item["user_id"])
+				}
+			},
+		},
 	}
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {