diff --git a/Endpoints/TelegramEndpoint.cs b/Endpoints/TelegramEndpoint.cs
index 6d382d5..6014b63 100644
--- a/Endpoints/TelegramEndpoint.cs
+++ b/Endpoints/TelegramEndpoint.cs
@@ -81,8 +81,9 @@ public static class TelegramEndpoint
         var body = await JsonSerializer.DeserializeAsync<JsonElement>(req.Body);
         var botToken = body.TryGetProperty("botToken", out var t) ? t.GetString() : null;
         var webhookSecret = body.TryGetProperty("webhookSecret", out var s) ? s.GetString() : null;
+        var allowedChatIds = body.TryGetProperty("allowedChatIds", out var a) ? a.GetString() : session.TelegramAllowedChatIds;
 
-        await db.UpdateSessionTelegram(sessionId, botToken, webhookSecret, session.TelegramChatId);
+        await db.UpdateSessionTelegram(sessionId, botToken, webhookSecret, session.TelegramChatId, allowedChatIds);
         await res.WriteAsJsonAsync(new { ok = true });
     }
 
@@ -102,6 +103,7 @@ public static class TelegramEndpoint
             botToken = session.TelegramBotToken ?? "",
             webhookSecret = session.TelegramWebhookSecret ?? "",
             chatId = session.TelegramChatId ?? "",
+            allowedChatIds = session.TelegramAllowedChatIds ?? "",
             configured = !string.IsNullOrEmpty(session.TelegramBotToken)
         });
     }
diff --git a/Models/SessionRecord.cs b/Models/SessionRecord.cs
index a1eca00..85598ec 100644
--- a/Models/SessionRecord.cs
+++ b/Models/SessionRecord.cs
@@ -16,6 +16,7 @@ public class SessionRecord
     public string TelegramBotToken { get; set; }
     public string TelegramWebhookSecret { get; set; }
     public string TelegramChatId { get; set; }
+    public string TelegramAllowedChatIds { get; set; }
     public double AvatarScale { get; set; } = 1.0;
     public string CreatedAt { get; set; }
     public string UpdatedAt { get; set; }
diff --git a/Services/DatabaseService.cs b/Services/DatabaseService.cs
index dfd9ddb..9a3f7bf 100644
--- a/Services/DatabaseService.cs
+++ b/Services/DatabaseService.cs
@@ -162,6 +162,7 @@ public class DatabaseService
         TryAddColumn(conn, "sessions", "telegram_bot_token", "TEXT");
         TryAddColumn(conn, "sessions", "telegram_webhook_secret", "TEXT");
         TryAddColumn(conn, "sessions", "telegram_chat_id", "TEXT");
+        TryAddColumn(conn, "sessions", "telegram_allowed_chat_ids", "TEXT");
         TryAddColumn(conn, "agents", "user_id", "TEXT");
         TryAddColumn(conn, "users", "is_admin", "INTEGER NOT NULL DEFAULT 0");
         TryAddColumn(conn, "users", "persona", "TEXT");
@@ -956,14 +957,14 @@ public class DatabaseService
             new { chatId = chatId.ToString() });
     }
 
-    public async Task UpdateSessionTelegram(string sessionId, string botToken, string webhookSecret, string chatId)
+    public async Task UpdateSessionTelegram(string sessionId, string botToken, string webhookSecret, string chatId, string allowedChatIds = null)
     {
         using var conn = CreateConnection();
         await conn.ExecuteAsync(@"
             UPDATE sessions SET telegram_bot_token = @botToken, telegram_webhook_secret = @webhookSecret,
-                telegram_chat_id = @chatId, updated_at = @now
+                telegram_chat_id = @chatId, telegram_allowed_chat_ids = @allowedChatIds, updated_at = @now
             WHERE session_id = @sessionId",
-            new { sessionId, botToken, webhookSecret, chatId, now = DateTime.UtcNow.ToString("o") });
+            new { sessionId, botToken, webhookSecret, chatId, allowedChatIds, now = DateTime.UtcNow.ToString("o") });
     }
 
     public async Task SetSessionTelegramChatId(string sessionId, string chatId)
diff --git a/Services/TelegramService.cs b/Services/TelegramService.cs
index 4eda3f8..5688028 100644
--- a/Services/TelegramService.cs
+++ b/Services/TelegramService.cs
@@ -60,7 +60,46 @@ public class TelegramService
 
         if (text.StartsWith("/start"))
         {
-            await _db.SetSessionTelegramChatId(session.SessionId, chatId.ToString());
+            if (!IsChatIdAllowed(session, chatId))
+            {
+                // Telegram-Username aus dem Update extrahieren
+                var username = "";
+                if (message.TryGetProperty("from", out var from))
+                {
+                    if (from.TryGetProperty("username", out var uname))
+                        username = uname.GetString() ?? "";
+                    else if (from.TryGetProperty("first_name", out var fname))
+                        username = fname.GetString() ?? "";
+                }
+
+                await SendMessage(chatId, botToken,
+                    "🔒 Zugriff verweigert.\n\n" +
+                    "Du bist nicht für diesen Bot freigegeben. " +
+                    "Bitte kontaktiere den Inhaber und teile deine Chat-ID mit:\n\n" +
+                    $"📋 Deine Chat-ID: `{chatId}`",
+                    parseMode: "Markdown");
+
+                // Owner benachrichtigen (wenn chatId gesetzt)
+                if (!string.IsNullOrEmpty(session.TelegramChatId))
+                {
+                    var ownerChatId = long.Parse(session.TelegramChatId);
+                    var requesterInfo = string.IsNullOrEmpty(username) ? chatId.ToString() : $"@{username} ({chatId})";
+                    await SendMessage(ownerChatId, botToken,
+                        $"🔔 *Zugriffsanfrage*\n\n" +
+                        $"Benutzer {EscapeMd(requesterInfo)} möchte diesen Bot nutzen\\.\n\n" +
+                        $"Chat\\-ID: `{chatId}`\n\n" +
+                        "Zum Freigeben: Chat\\-ID in den Session\\-Einstellungen unter _Erlaubte Chat\\-IDs_ hinzufügen\\.",
+                        parseMode: "MarkdownV2");
+                }
+                return;
+            }
+
+            // Erste Verbindung: chatId als Owner setzen (wenn noch keine gesetzt)
+            if (string.IsNullOrEmpty(session.TelegramChatId))
+            {
+                await _db.SetSessionTelegramChatId(session.SessionId, chatId.ToString());
+            }
+
             var sessionName = session.Name ?? session.SessionId;
             await SendMessage(chatId, botToken,
                 $"✅ *Verbunden mit Session: {EscapeMd(sessionName)}*\n\n" +
@@ -73,6 +112,13 @@ public class TelegramService
             return;
         }
 
+        // Alle anderen Befehle/Nachrichten: Zugriff prüfen
+        if (!IsChatIdAllowed(session, chatId))
+        {
+            await SendMessage(chatId, botToken, "🔒 Du bist nicht für diesen Bot freigegeben. Sende /start für mehr Informationen.");
+            return;
+        }
+
         if (text.StartsWith("/"))
         {
             await HandleCommand(chatId, text, botToken, session);
@@ -122,9 +168,9 @@ public class TelegramService
 
     private async Task HandleMessage(long chatId, string userText, string botToken, SessionRecord session)
     {
-        if (session.TelegramChatId != chatId.ToString())
+        if (!IsChatIdAllowed(session, chatId))
         {
-            await SendMessage(chatId, botToken, "❌ Bitte sende zuerst /start um dich mit dieser Session zu verbinden.");
+            await SendMessage(chatId, botToken, "🔒 Du bist nicht für diesen Bot freigegeben. Sende /start für mehr Informationen.");
             return;
         }
 
@@ -280,6 +326,30 @@ public class TelegramService
 
     // ── Helper ──
 
+    private static bool IsChatIdAllowed(SessionRecord session, long chatId)
+    {
+        var chatIdStr = chatId.ToString();
+
+        // Owner (die primäre verknüpfte chatId) ist immer erlaubt
+        if (session.TelegramChatId == chatIdStr) return true;
+
+        // Wenn noch kein Owner gesetzt und keine Whitelist → erster User wird Owner
+        if (string.IsNullOrEmpty(session.TelegramChatId) && string.IsNullOrEmpty(session.TelegramAllowedChatIds))
+            return true;
+
+        // Whitelist prüfen
+        if (!string.IsNullOrEmpty(session.TelegramAllowedChatIds))
+        {
+            var allowed = session.TelegramAllowedChatIds.Split(',', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+            foreach (var id in allowed)
+            {
+                if (id == chatIdStr) return true;
+            }
+        }
+
+        return false;
+    }
+
     private static string EscapeMd(string text)
     {
         if (string.IsNullOrEmpty(text)) return "";
diff --git a/wwwroot/index.html b/wwwroot/index.html
index 31150f8..565b9d6 100644
--- a/wwwroot/index.html
+++ b/wwwroot/index.html
@@ -127,6 +127,9 @@
             <input type="text" id="sessionTelegramToken" placeholder="123456:ABC-DEF..." autocomplete="off">
             <label>Webhook-Secret</label>
             <input type="text" id="sessionTelegramSecret" readonly style="opacity: var(--semi-transparent); ">
+            <label>Erlaubte Chat-IDs</label>
+            <input type="text" id="sessionTelegramAllowed" placeholder="Kommagetrennt, z.B. 123456,789012">
+            <small class="form-hint">Der verknüpfte Owner ist automatisch erlaubt. Weitere Chat-IDs hier eintragen.</small>
             <label>Status</label>
             <div id="sessionTelegramStatusBox" class="telegram-status-box">Kein Status verfügbar</div>
             <div class="telegram-actions">
diff --git a/wwwroot/js/api.js b/wwwroot/js/api.js
index 3b94419..bdea648 100644
--- a/wwwroot/js/api.js
+++ b/wwwroot/js/api.js
@@ -271,11 +271,11 @@ async function apiSessionTelegramGet(sessionId) {
   return resp.json();
 }
 
-async function apiSessionTelegramSave(sessionId, botToken, webhookSecret) {
+async function apiSessionTelegramSave(sessionId, botToken, webhookSecret, allowedChatIds) {
   const resp = await fetch(`/api/sessions/${sessionId}/telegram`, {
     method: 'PUT',
     headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ botToken, webhookSecret })
+    body: JSON.stringify({ botToken, webhookSecret, allowedChatIds })
   });
   if (!resp.ok) {
     const err = await resp.json().catch(() => ({}));
diff --git a/wwwroot/js/pages/session-page.js b/wwwroot/js/pages/session-page.js
index b0929de..b777bf7 100644
--- a/wwwroot/js/pages/session-page.js
+++ b/wwwroot/js/pages/session-page.js
@@ -180,6 +180,7 @@ registerPage('session', {
 function initSessionTelegram(sessionId) {
   var tokenInput = document.getElementById('sessionTelegramToken');
   var secretInput = document.getElementById('sessionTelegramSecret');
+  var allowedInput = document.getElementById('sessionTelegramAllowed');
   var registerBtn = document.getElementById('sessionTelegramRegisterBtn');
   var deleteBtn = document.getElementById('sessionTelegramDeleteBtn');
   var statusBox = document.getElementById('sessionTelegramStatusBox');
@@ -187,6 +188,7 @@ function initSessionTelegram(sessionId) {
   // Vorhandene Config laden + Status abrufen
   apiSessionTelegramGet(sessionId).then(async function(config) {
     if (config.botToken) tokenInput.value = config.botToken;
+    if (config.allowedChatIds) allowedInput.value = config.allowedChatIds;
     if (config.webhookSecret) {
       secretInput.value = config.webhookSecret;
     } else {
@@ -294,7 +296,9 @@ async function refreshTelegramStatus(sessionId, statusBox, registerBtn, deleteBt
 async function saveTelegramConfig(sessionId, tokenInput, secretInput) {
   var token = tokenInput.value.trim();
   var secret = secretInput.value.trim();
-  await apiSessionTelegramSave(sessionId, token, secret);
+  var allowedInput = document.getElementById('sessionTelegramAllowed');
+  var allowed = allowedInput ? allowedInput.value.trim() : '';
+  await apiSessionTelegramSave(sessionId, token, secret, allowed);
 }
 
 function escapeHtml(str) {