diff --git a/frontend/constants/supabase.ts b/frontend/constants/supabase.ts
index 4334da2..513ad7f 100644
--- a/frontend/constants/supabase.ts
+++ b/frontend/constants/supabase.ts
@@ -12,6 +12,7 @@ export const TABLES = {
   PUSH_TOKENS: 'push_tokens',
   NOTIFICATION_SETTINGS: 'notification_settings',
   PRIVACY_SETTINGS: 'privacy_settings',
+  USER_STREAKS: 'user_streaks',
 } as const;
 
 // Storage Bucket Names
@@ -120,5 +121,15 @@ export const SCHEMA = {
     location_share: 'boolean NOT NULL DEFAULT true',
     created_at: 'timestamptz DEFAULT now()',
     updated_at: 'timestamptz DEFAULT now()',
+  },
+  USER_STREAKS: {
+    id: 'bigserial PRIMARY KEY',
+    user_id: 'uuid NOT NULL REFERENCES auth.users(id) ON DELETE CASCADE',
+    current_streak: 'integer NOT NULL DEFAULT 0',
+    max_streak: 'integer NOT NULL DEFAULT 0',
+    last_entry_date: 'date',
+    last_access_time: 'timestamptz',
+    created_at: 'timestamptz DEFAULT now()',
+    updated_at: 'timestamptz DEFAULT now()',
   }
 } as const;
\ No newline at end of file
diff --git a/frontend/services/streak-service.ts b/frontend/services/streak-service.ts
index b1a8ca6..f44ace2 100644
--- a/frontend/services/streak-service.ts
+++ b/frontend/services/streak-service.ts
@@ -1,6 +1,7 @@
 import { format, differenceInDays, startOfDay } from 'date-fns';
 import { deviceStorage } from './device-storage';
 import { logger } from '@/lib/logger';
+import { supabase } from '@/lib/supabase';
 
 /**
  * Streak Service - Manages user daily entry streaks
@@ -40,6 +41,42 @@ export class StreakService {
       console.error('Failed to load streak data:', error);
     }
 
+    // Fallback to Supabase (single row per user) for cross-device sync of streak data
+    try {
+      const { data, error } = await supabase
+        .from('user_streaks')
+        .select('current_streak, max_streak, last_entry_date, last_access_time')
+        .eq('user_id', userId)
+        .maybeSingle<{
+          current_streak: number | null;
+          max_streak: number | null;
+          last_entry_date: string | null;
+          last_access_time: string | null;
+        }>();
+
+      if (error) {
+        console.error('Error fetching streak data from Supabase:', error);
+      } else if (data) {
+        const fromRemote: StreakData = {
+          currentStreak: data.current_streak ?? 0,
+          maxStreak: data.max_streak ?? 0,
+          lastEntryDate: data.last_entry_date,
+          lastAccessTime: data.last_access_time,
+        };
+
+        // Cache remotely-loaded data locally (best-effort)
+        try {
+          await deviceStorage.setItem(`streak_${userId}`, fromRemote);
+        } catch (cacheError) {
+          console.error('Failed to cache remote streak data locally:', cacheError);
+        }
+
+        return fromRemote;
+      }
+    } catch (error) {
+      console.error('Error in Supabase streak fallback:', error);
+    }
+
     // Return default streak data
     return {
       currentStreak: 0,
@@ -51,12 +88,32 @@ export class StreakService {
 
   // Save streak data to storage
   static async saveStreakData(userId: string, data: StreakData): Promise<void> {
+    // 1. Save to local storage (best-effort cache; don't throw)
     try {
       await deviceStorage.setItem(`streak_${userId}`, data);
       console.log('Saved streak data:', data);
     } catch (error) {
       console.error('Failed to save streak data:', error);
     }
+
+    // 2. Sync streak stats to Supabase (best-effort; do not block core app flows)
+    try {
+      const { error } = await supabase
+        .from('user_streaks')
+        .upsert({
+          user_id: userId,
+          current_streak: data.currentStreak,
+          max_streak: data.maxStreak,
+          last_entry_date: data.lastEntryDate,
+          last_access_time: data.lastAccessTime,
+        } as never, { onConflict: 'user_id' } as never);
+
+      if (error) {
+        console.error('Error saving streak data to Supabase:', error);
+      }
+    } catch (error) {
+      console.error('Error in saveStreakData Supabase sync:', error);
+    }
   }
 
   /**
diff --git a/frontend/supabase/migrations/20260111000000_streaks.sql b/frontend/supabase/migrations/20260111000000_streaks.sql
new file mode 100644
index 0000000..789b51c
--- /dev/null
+++ b/frontend/supabase/migrations/20260111000000_streaks.sql
@@ -0,0 +1,83 @@
+/*
+  # User Streaks Table
+
+  1. New Table
+    - `user_streaks` - Per-user streak stats (1 row per user)
+      - `id` (bigint, primary key)
+      - `user_id` (uuid, references auth.users)
+      - `current_streak` (integer)
+      - `max_streak` (integer)
+      - `last_entry_date` (date, nullable)
+      - `last_access_time` (timestamptz, nullable)
+      - `created_at` (timestamp)
+      - `updated_at` (timestamp)
+
+  2. Security
+    - Enable RLS
+    - Policies so users can manage only their own streak record
+*/
+
+-- Create user_streaks table
+CREATE TABLE IF NOT EXISTS user_streaks (
+  id bigserial PRIMARY KEY,
+  user_id uuid NOT NULL REFERENCES auth.users(id) ON DELETE CASCADE,
+  current_streak integer NOT NULL DEFAULT 0,
+  max_streak integer NOT NULL DEFAULT 0,
+  last_entry_date date,
+  last_access_time timestamptz,
+  created_at timestamptz NOT NULL DEFAULT now(),
+  updated_at timestamptz NOT NULL DEFAULT now()
+);
+
+-- Backfill and enforce NOT NULL constraints for existing rows (if any)
+UPDATE user_streaks
+SET created_at = now()
+WHERE created_at IS NULL;
+
+UPDATE user_streaks
+SET updated_at = now()
+WHERE updated_at IS NULL;
+
+ALTER TABLE user_streaks
+  ALTER COLUMN created_at SET NOT NULL,
+  ALTER COLUMN updated_at SET NOT NULL;
+
+-- Enable Row Level Security
+ALTER TABLE user_streaks ENABLE ROW LEVEL SECURITY;
+
+-- Policies: users can manage their own streak record
+CREATE POLICY "Users can read own streak"
+  ON user_streaks
+  FOR SELECT
+  TO authenticated
+  USING (auth.uid() = user_id);
+
+CREATE POLICY "Users can insert own streak"
+  ON user_streaks
+  FOR INSERT
+  TO authenticated
+  WITH CHECK (auth.uid() = user_id);
+
+CREATE POLICY "Users can update own streak"
+  ON user_streaks
+  FOR UPDATE
+  TO authenticated
+  USING (auth.uid() = user_id)
+  WITH CHECK (auth.uid() = user_id);
+
+CREATE POLICY "Users can delete own streak"
+  ON user_streaks
+  FOR DELETE
+  TO authenticated
+  USING (auth.uid() = user_id);
+
+-- Indexes for performance
+CREATE UNIQUE INDEX IF NOT EXISTS idx_user_streaks_user_id
+  ON user_streaks(user_id);
+
+-- updated_at trigger
+CREATE TRIGGER update_user_streaks_updated_at
+  BEFORE UPDATE ON user_streaks
+  FOR EACH ROW
+  EXECUTE FUNCTION update_updated_at_column();
+
diff --git a/frontend/types/database.ts b/frontend/types/database.ts
index b493d76..a59b233 100644
--- a/frontend/types/database.ts
+++ b/frontend/types/database.ts
@@ -317,6 +317,38 @@ export interface Database {
           updated_at?: string
         }
       }
+      user_streaks: {
+        Row: {
+          id: number
+          user_id: string
+          current_streak: number
+          max_streak: number
+          last_entry_date: string | null
+          last_access_time: string | null
+          created_at: string
+          updated_at: string
+        }
+        Insert: {
+          id?: number
+          user_id: string
+          current_streak?: number
+          max_streak?: number
+          last_entry_date?: string | null
+          last_access_time?: string | null
+          created_at?: string
+          updated_at?: string
+        }
+        Update: {
+          id?: number
+          user_id?: string
+          current_streak?: number
+          max_streak?: number
+          last_entry_date?: string | null
+          last_access_time?: string | null
+          created_at?: string
+          updated_at?: string
+        }
+      }
     }
     Views: {
       [_ in never]: never