diff --git a/api/config.py b/api/config.py
index 77127bf7..24ef46a8 100644
--- a/api/config.py
+++ b/api/config.py
@@ -4324,6 +4324,7 @@ _SETTINGS_DEFAULTS = {
     "font_size": "default",  # small | default | large | xlarge
     "session_jump_buttons": False,  # show Start/End transcript jump pills
     "session_endless_scroll": False,  # auto-load older transcript pages while scrolling upward
+    "pinned_sessions_limit": 3,  # maximum active pinned sessions shown in the sidebar
     "hidden_tabs": [],  # sidebar tab panel names hidden by user (e.g. ["tasks","kanban"]); chat and settings are always visible
     "language": "en",  # UI locale code; must match a key in static/i18n.js LOCALES
     "bot_name": os.getenv(
@@ -4452,6 +4453,9 @@ _SETTINGS_ENUM_VALUES = {
     "auto_title_refresh_every": {"0", "5", "10", "20"},
     "busy_input_mode": {"queue", "interrupt", "steer"},
 }
+_SETTINGS_INT_RANGES = {
+    "pinned_sessions_limit": (1, 99),
+}
 _SETTINGS_BOOL_KEYS = {
     "onboarding_completed",
     "show_token_usage",
@@ -4512,6 +4516,15 @@ def save_settings(settings: dict) -> dict:
             # Validate enum-constrained keys
             if k in _SETTINGS_ENUM_VALUES and v not in _SETTINGS_ENUM_VALUES[k]:
                 continue
+            # Validate bounded integer settings.
+            if k in _SETTINGS_INT_RANGES:
+                try:
+                    v = int(v)
+                except (TypeError, ValueError):
+                    continue
+                min_value, max_value = _SETTINGS_INT_RANGES[k]
+                if v < min_value or v > max_value:
+                    continue
             # Validate language codes (BCP-47-like: 'en', 'zh', 'fr', 'zh-CN')
             if k == "language" and (
                 not isinstance(v, str) or not _SETTINGS_LANG_RE.match(v)
diff --git a/api/routes.py b/api/routes.py
index c7f287ac..54c6261b 100644
--- a/api/routes.py
+++ b/api/routes.py
@@ -5767,8 +5767,9 @@ def handle_post(handler, parsed) -> bool:
                     if getattr(existing, "pinned", False) and not getattr(existing, "archived", False)
                 )
                 pinned_ids.discard(body["session_id"])
-                if len(pinned_ids) >= 3:
-                    return bad(handler, "Up to 3 sessions can be pinned. Unpin one before pinning another.", 400)
+                pinned_sessions_limit = int(load_settings().get("pinned_sessions_limit", 3) or 3)
+                if len(pinned_ids) >= pinned_sessions_limit:
+                    return bad(handler, f"Up to {pinned_sessions_limit} sessions can be pinned. Unpin one before pinning another.", 400)
                 # Mark in-memory pin state under LOCK so concurrent pin
                 # requests see the increment immediately, even before
                 # save() finishes flushing to disk.
diff --git a/static/boot.js b/static/boot.js
index 61688c49..9b48b910 100644
--- a/static/boot.js
+++ b/static/boot.js
@@ -1451,6 +1451,7 @@ function applyBotName(){
     window._showThinking=s.show_thinking!==false;
     window._simplifiedToolCalling=s.simplified_tool_calling!==false;
     window._sidebarDensity=(s.sidebar_density==='detailed'?'detailed':'compact');
+    window._pinnedSessionsLimit=parseInt(s.pinned_sessions_limit||3,10)||3;
     window._busyInputMode=(s.busy_input_mode||'queue');
     window._sessionEndlessScrollEnabled=!!s.session_endless_scroll;
     window._botName=s.bot_name||'Hermes';
@@ -1539,6 +1540,7 @@ function applyBotName(){
     window._simplifiedToolCalling=true;
     window._sessionJumpButtonsEnabled=false;
     window._sidebarDensity='compact';
+    window._pinnedSessionsLimit=3;
     window._busyInputMode='queue';
     window._sessionEndlessScrollEnabled=false;
     window._botName='Hermes';
diff --git a/static/index.html b/static/index.html
index bb8e86c4..1659189f 100644
--- a/static/index.html
+++ b/static/index.html
@@ -1126,6 +1126,11 @@
               </select>
               <div style="font-size:11px;color:var(--muted);margin-top:4px" data-i18n="settings_desc_sidebar_density">Controls how much metadata the session list shows in the left sidebar.</div>
             </div>
+            <div class="settings-field">
+              <label for="settingsPinnedSessionsLimit">Pinned conversations limit</label>
+              <input type="number" id="settingsPinnedSessionsLimit" min="1" max="99" step="1" inputmode="numeric" style="width:100%;padding:8px;background:var(--code-bg);color:var(--text);border:1px solid var(--border2);border-radius:6px;font-size:13px">
+              <div style="font-size:11px;color:var(--muted);margin-top:4px">Maximum number of active conversations that can be pinned in the sidebar. Default is 3.</div>
+            </div>
             <div class="settings-field">
               <label for="settingsAutoTitleRefresh" data-i18n="settings_label_auto_title_refresh">Adaptive title refresh</label>
               <select id="settingsAutoTitleRefresh" style="width:100%;padding:8px;background:var(--code-bg);color:var(--text);border:1px solid var(--border2);border-radius:6px">
diff --git a/static/panels.js b/static/panels.js
index 495ea3c8..21af3eec 100644
--- a/static/panels.js
+++ b/static/panels.js
@@ -5442,6 +5442,8 @@ function _preferencesPayloadFromUi(){
   if(notifCb) payload.notifications_enabled=notifCb.checked;
   const sidebarDensitySel=$('settingsSidebarDensity');
   if(sidebarDensitySel) payload.sidebar_density=sidebarDensitySel.value;
+  const pinnedLimitField=$('settingsPinnedSessionsLimit');
+  if(pinnedLimitField) payload.pinned_sessions_limit=parseInt(pinnedLimitField.value,10);
   const autoTitleRefreshSel=$('settingsAutoTitleRefresh');
   if(autoTitleRefreshSel) payload.auto_title_refresh_every=parseInt(autoTitleRefreshSel.value,10);
   const busyInputModeSel=$('settingsBusyInputMode');
@@ -5493,6 +5495,7 @@ async function _autosavePreferencesSettings(payload){
       if(typeof renderMessages==='function') renderMessages();
     }
     if(payload&&Object.prototype.hasOwnProperty.call(payload,'fade_text_effect')) window._fadeTextEffect=!!payload.fade_text_effect;
+    if(saved&&Object.prototype.hasOwnProperty.call(saved,'pinned_sessions_limit')) window._pinnedSessionsLimit=parseInt(saved.pinned_sessions_limit,10)||3;
     if(payload&&payload.show_tps!==undefined){
       window._showTps=!!(saved&&saved.show_tps);
       if(typeof clearMessageRenderCache==='function') clearMessageRenderCache();
@@ -5699,6 +5702,13 @@ async function loadSettingsPanel(){
     }
     const showTpsCb=$('settingsShowTps');
     if(showTpsCb){showTpsCb.checked=!!settings.show_tps;showTpsCb.addEventListener('change',_schedulePreferencesAutosave,{once:false});}
+    const pinnedLimitField=$('settingsPinnedSessionsLimit');
+    if(pinnedLimitField){
+      pinnedLimitField.value=parseInt(settings.pinned_sessions_limit||3,10)||3;
+      window._pinnedSessionsLimit=parseInt(pinnedLimitField.value,10)||3;
+      pinnedLimitField.addEventListener('change',_schedulePreferencesAutosave,{once:false});
+      pinnedLimitField.addEventListener('input',()=>{window._pinnedSessionsLimit=parseInt(pinnedLimitField.value,10)||3;_schedulePreferencesAutosave();},{once:false});
+    }
     const fadeTextCb=$('settingsFadeTextEffect');
     if(fadeTextCb){fadeTextCb.checked=!!settings.fade_text_effect;window._fadeTextEffect=fadeTextCb.checked;fadeTextCb.addEventListener('change',_schedulePreferencesAutosave,{once:false});}
     const simplifiedToolCb=$('settingsSimplifiedToolCalling');
@@ -6604,6 +6614,7 @@ async function saveSettings(andClose){
   const fadeTextEffect=!!($('settingsFadeTextEffect')||{}).checked;
   const showCliSessions=!!($('settingsShowCliSessions')||{}).checked;
   const showPreviousMessagingSessions=!!($('settingsShowPreviousMessagingSessions')||{}).checked;
+  const pinnedSessionsLimit=parseInt(($('settingsPinnedSessionsLimit')||{}).value,10)||3;
   const pw=($('settingsPassword')||{}).value;
   const theme=($('settingsTheme')||{}).value||'dark';
   const skin=($('settingsSkin')||{}).value||'default';
@@ -6628,6 +6639,7 @@ async function saveSettings(andClose){
   body.api_redact_enabled=!!($('settingsApiRedact')||{}).checked;
   body.show_cli_sessions=showCliSessions;
   body.show_previous_messaging_sessions=showPreviousMessagingSessions;
+  body.pinned_sessions_limit=pinnedSessionsLimit;
   body.sync_to_insights=!!($('settingsSyncInsights')||{}).checked;
   body.check_for_updates=!!($('settingsCheckUpdates')||{}).checked;
   body.whats_new_summary_enabled=!!($('settingsWhatsNewSummary')||{}).checked;
diff --git a/static/sessions.js b/static/sessions.js
index 5e57b354..1c21d17e 100644
--- a/static/sessions.js
+++ b/static/sessions.js
@@ -1481,6 +1481,14 @@ function _sessionSnapshotById(sid){
 function _pinnedSessionCount(){
   return (_allSessions||[]).filter(s=>s&&s.pinned&&!s.archived).length;
 }
+function _pinnedSessionsLimit(){
+  const limit=parseInt(window._pinnedSessionsLimit||3,10);
+  return (Number.isFinite(limit)&&limit>0)?limit:3;
+}
+function _pinnedSessionsLimitMessage(){
+  const limit=_pinnedSessionsLimit();
+  return `Only ${limit} conversations can be pinned. Unpin one before pinning another.`;
+}
 function _worktreeSessionCount(ids){
   return (ids||[]).reduce((count,sid)=>{
     const session=_sessionSnapshotById(sid);
@@ -1791,15 +1799,15 @@ function _openSessionActionMenu(session, anchorEl){
       }
     ));
   }
-  const pinLimitReached=!session.pinned&&_pinnedSessionCount()>=3;
+  const pinLimitReached=!session.pinned&&_pinnedSessionCount()>=_pinnedSessionsLimit();
   menu.appendChild(_buildSessionAction(
     session.pinned?t('session_unpin'):t('session_pin'),
-    pinLimitReached?'Only 3 conversations can be pinned':(session.pinned?t('session_unpin_desc'):t('session_pin_desc')),
+    pinLimitReached?_pinnedSessionsLimitMessage():(session.pinned?t('session_unpin_desc'):t('session_pin_desc')),
     session.pinned?ICONS.pin:ICONS.unpin,
     async()=>{
       closeSessionActionMenu();
       if(pinLimitReached){
-        if(typeof showToast==='function') showToast('Only 3 conversations can be pinned. Unpin one before pinning another.',3000,'error');
+        if(typeof showToast==='function') showToast(_pinnedSessionsLimitMessage(),3000,'error');
         return;
       }
       const newPinned=!session.pinned;
diff --git a/tests/test_configurable_pinned_sessions_limit.py b/tests/test_configurable_pinned_sessions_limit.py
new file mode 100644
index 00000000..07dae3f7
--- /dev/null
+++ b/tests/test_configurable_pinned_sessions_limit.py
@@ -0,0 +1,100 @@
+"""Regression checks for configurable pinned session limits."""
+
+import json
+import pathlib
+import urllib.error
+import urllib.request
+
+from tests._pytest_port import BASE
+
+ROOT = pathlib.Path(__file__).resolve().parent.parent
+CONFIG_PY = (ROOT / "api" / "config.py").read_text(encoding="utf-8")
+INDEX_HTML = (ROOT / "static" / "index.html").read_text(encoding="utf-8")
+PANELS_JS = (ROOT / "static" / "panels.js").read_text(encoding="utf-8")
+BOOT_JS = (ROOT / "static" / "boot.js").read_text(encoding="utf-8")
+SESSIONS_JS = (ROOT / "static" / "sessions.js").read_text(encoding="utf-8")
+
+
+def post(path, body=None):
+    data = json.dumps(body or {}).encode()
+    req = urllib.request.Request(
+        BASE + path,
+        data=data,
+        headers={"Content-Type": "application/json"},
+    )
+    try:
+        with urllib.request.urlopen(req, timeout=10) as r:
+            return json.loads(r.read()), r.status
+    except urllib.error.HTTPError as e:
+        return json.loads(e.read()), e.code
+
+
+def make_session(created, title):
+    payload = {
+        "title": title,
+        "messages": [{"role": "user", "content": "keep this conversation handy"}],
+        "model": "test/pin-limit-setting",
+    }
+    d, status = post("/api/session/import", payload)
+    assert status == 200
+    sid = d["session"]["session_id"]
+    created.append(sid)
+    return sid
+
+
+def test_pin_limit_setting_is_exposed_and_wired_through_ui():
+    assert '"pinned_sessions_limit": 3' in CONFIG_PY
+    assert '"pinned_sessions_limit": (1, 99)' in CONFIG_PY
+    assert 'id="settingsPinnedSessionsLimit"' in INDEX_HTML
+    assert 'type="number"' in INDEX_HTML
+    assert 'min="1"' in INDEX_HTML
+    assert 'max="99"' in INDEX_HTML
+    assert 'payload.pinned_sessions_limit=parseInt(pinnedLimitField.value,10)' in PANELS_JS
+    assert "settings.pinned_sessions_limit" in PANELS_JS
+    assert "window._pinnedSessionsLimit=parseInt(s.pinned_sessions_limit||3,10)||3" in BOOT_JS
+    assert "function _pinnedSessionsLimit()" in SESSIONS_JS
+    assert "_pinnedSessionCount()>=_pinnedSessionsLimit()" in SESSIONS_JS
+
+
+def test_settings_api_persists_integer_pin_limit_and_rejects_invalid_values():
+    try:
+        d, status = post("/api/settings", {"pinned_sessions_limit": 5})
+        assert status == 200
+        assert d["pinned_sessions_limit"] == 5
+
+        d, status = post("/api/settings", {"pinned_sessions_limit": "7"})
+        assert status == 200
+        assert d["pinned_sessions_limit"] == 7
+
+        d, status = post("/api/settings", {"pinned_sessions_limit": 0})
+        assert status == 200
+        assert d["pinned_sessions_limit"] == 7
+
+        d, status = post("/api/settings", {"pinned_sessions_limit": 100})
+        assert status == 200
+        assert d["pinned_sessions_limit"] == 7
+    finally:
+        post("/api/settings", {"pinned_sessions_limit": 3})
+
+
+def test_session_pin_endpoint_uses_configured_limit():
+    created = []
+    try:
+        d, status = post("/api/settings", {"pinned_sessions_limit": 4})
+        assert status == 200
+        assert d["pinned_sessions_limit"] == 4
+
+        pinned = [make_session(created, f"Configured pin cap {i}") for i in range(4)]
+        for sid in pinned:
+            d, status = post("/api/session/pin", {"session_id": sid, "pinned": True})
+            assert status == 200
+            assert d["session"]["pinned"] is True
+
+        fifth = make_session(created, "Configured pin cap overflow")
+        d, status = post("/api/session/pin", {"session_id": fifth, "pinned": True})
+        assert status == 400
+        assert "4 sessions" in d.get("error", "")
+    finally:
+        post("/api/settings", {"pinned_sessions_limit": 3})
+        for sid in created:
+            post("/api/session/delete", {"session_id": sid})
diff --git a/tests/test_issue2508_session_pin_cap.py b/tests/test_issue2508_session_pin_cap.py
index b629c7f5..7053f9a7 100644
--- a/tests/test_issue2508_session_pin_cap.py
+++ b/tests/test_issue2508_session_pin_cap.py
@@ -70,12 +70,14 @@ def test_session_pin_endpoint_caps_pinned_sessions_at_three():
 def test_session_pin_cap_has_backend_and_frontend_guards():
     assert 'pinned_ids = {' in ROUTES_PY
     assert 'pinned_ids.update(' in ROUTES_PY
-    assert 'if len(pinned_ids) >= 3:' in ROUTES_PY
-    assert 'Up to 3 sessions can be pinned' in ROUTES_PY
+    assert 'pinned_sessions_limit = int(load_settings().get("pinned_sessions_limit", 3) or 3)' in ROUTES_PY
+    assert 'if len(pinned_ids) >= pinned_sessions_limit:' in ROUTES_PY
+    assert 'Up to {pinned_sessions_limit} sessions can be pinned' in ROUTES_PY
 
     assert 'function _pinnedSessionCount()' in SESSIONS_JS
-    assert 'const pinLimitReached=!session.pinned&&_pinnedSessionCount()>=3;' in SESSIONS_JS
-    assert "Only 3 conversations can be pinned" in SESSIONS_JS
+    assert 'function _pinnedSessionsLimit()' in SESSIONS_JS
+    assert 'const pinLimitReached=!session.pinned&&_pinnedSessionCount()>=_pinnedSessionsLimit();' in SESSIONS_JS
+    assert 'Only ${limit} conversations can be pinned' in SESSIONS_JS
     assert ".session-action-opt.is-disabled{opacity:.55;cursor:not-allowed;}" in STYLE_CSS