diff --git a/drizzle/0025_assistant_model.sql b/drizzle/0025_assistant_model.sql
new file mode 100644
index 0000000..c612126
--- /dev/null
+++ b/drizzle/0025_assistant_model.sql
@@ -0,0 +1 @@
+ALTER TABLE "users" ADD COLUMN "assistant_model" text;
diff --git a/drizzle/meta/_journal.json b/drizzle/meta/_journal.json
index 229b5ad..a0c11fb 100644
--- a/drizzle/meta/_journal.json
+++ b/drizzle/meta/_journal.json
@@ -176,6 +176,13 @@
       "when": 1780394000000,
       "tag": "0024_user_assistant_customization",
       "breakpoints": true
+    },
+    {
+      "idx": 25,
+      "version": "7",
+      "when": 1783560000000,
+      "tag": "0025_assistant_model",
+      "breakpoints": true
     }
   ]
 }
\ No newline at end of file
diff --git a/src/app/settings/assistant-actions.ts b/src/app/settings/assistant-actions.ts
index 0adfe98..385fd56 100644
--- a/src/app/settings/assistant-actions.ts
+++ b/src/app/settings/assistant-actions.ts
@@ -9,6 +9,7 @@ import {
   MAX_ASSISTANT_NAME_LENGTH,
   MAX_ASSISTANT_SYSTEM_PROMPT_LENGTH,
 } from "@/lib/assistant-config";
+import { isValidLlmModelId, listLlmModels } from "@/lib/llm/models";
 import { users } from "@/modules/_core/schema";
 import { getCurrentSession } from "@/lib/session";
 
@@ -50,6 +51,25 @@ export async function setAssistantSystemPrompt(prompt: string | null): Promise<v
   revalidateAssistantSurfaces();
 }
 
+export async function setAssistantModel(model: string | null): Promise<void> {
+  const { user } = await getCurrentSession();
+  const normalized = model?.trim() || null;
+
+  if (normalized !== null && !isValidLlmModelId(normalized)) {
+    throw new Error("Invalid assistant model");
+  }
+
+  const available = await listLlmModels();
+  const requested = normalized === available.fallbackModel ? null : normalized;
+
+  if (requested !== null && !available.models.some((option) => option.id === requested)) {
+    throw new Error("Invalid assistant model");
+  }
+
+  await db.update(users).set({ assistantModel: requested }).where(eq(users.id, user.id));
+  revalidateAssistantSurfaces();
+}
+
 export async function resetAssistantName(): Promise<void> {
   await setAssistantName(DEFAULT_ASSISTANT_NAME);
 }
diff --git a/src/lib/assistant-preference.ts b/src/lib/assistant-preference.ts
index b978671..babe897 100644
--- a/src/lib/assistant-preference.ts
+++ b/src/lib/assistant-preference.ts
@@ -14,6 +14,7 @@ export type AssistantPreferences = {
   enabled: boolean;
   name: string;
   systemPrompt: string | null;
+  model: string | null;
 };
 
 export async function getAssistantPreferences(userId: string): Promise<AssistantPreferences> {
@@ -22,6 +23,7 @@ export async function getAssistantPreferences(userId: string): Promise<Assistant
       assistantEnabled: users.assistantEnabled,
       assistantName: users.assistantName,
       assistantSystemPrompt: users.assistantSystemPrompt,
+      assistantModel: users.assistantModel,
     })
     .from(users)
     .where(eq(users.id, userId))
@@ -31,6 +33,7 @@ export async function getAssistantPreferences(userId: string): Promise<Assistant
     enabled: row?.assistantEnabled ?? false,
     name: row?.assistantName?.trim() || DEFAULT_ASSISTANT_NAME,
     systemPrompt: row?.assistantSystemPrompt ?? null,
+    model: row?.assistantModel?.trim() || null,
   };
 }
 
diff --git a/src/modules/_core/schema.ts b/src/modules/_core/schema.ts
index d5d2875..d404740 100644
--- a/src/modules/_core/schema.ts
+++ b/src/modules/_core/schema.ts
@@ -38,6 +38,7 @@ export const users = pgTable("users", {
   assistantEnabled: boolean("assistant_enabled").notNull().default(false),
   assistantName: text("assistant_name").notNull().default("Assistant"),
   assistantSystemPrompt: text("assistant_system_prompt"),
+  assistantModel: text("assistant_model"),
   defaultEventReminderOffsets: jsonb("default_event_reminder_offsets")
     .notNull()
     .$type<number[]>()