diff --git a/backup.sh b/backup.sh
new file mode 100755
index 0000000..e609b24
--- /dev/null
+++ b/backup.sh
@@ -0,0 +1,70 @@
+#!/usr/bin/env bash
+# backup.sh — restic backup of Cortex persona/home data
+#
+# Backs up the home/ directory (all user persona files, memory, tasks, crons).
+# Code is in git; this covers everything git intentionally excludes.
+#
+# Config — override via environment or edit here:
+REPO_DIR="${RESTIC_REPOSITORY:-$HOME/backups/cortex-home-restic}"
+PASSWORD_FILE="${RESTIC_PASSWORD_FILE:-$HOME/.config/cortex/restic-password}"
+SOURCE="$(cd "$(dirname "$0")" && pwd)/home"
+
+# Retention policy
+KEEP_DAILY=7
+KEEP_WEEKLY=4
+KEEP_MONTHLY=6
+
+# ── Preflight ─────────────────────────────────────────────────────────────────
+
+set -euo pipefail
+
+if ! command -v restic &>/dev/null; then
+    echo "ERROR: restic not found. Install with: sudo pacman -S restic" >&2
+    exit 1
+fi
+
+if [[ ! -d "$SOURCE" ]]; then
+    echo "ERROR: source directory not found: $SOURCE" >&2
+    exit 1
+fi
+
+# ── Password setup ────────────────────────────────────────────────────────────
+
+if [[ ! -f "$PASSWORD_FILE" ]]; then
+    mkdir -p "$(dirname "$PASSWORD_FILE")"
+    chmod 700 "$(dirname "$PASSWORD_FILE")"
+    python3 -c "import secrets; print(secrets.token_urlsafe(32))" > "$PASSWORD_FILE"
+    chmod 600 "$PASSWORD_FILE"
+    echo "Generated new restic password: $PASSWORD_FILE"
+    echo "IMPORTANT: back this file up separately — you need it to restore."
+fi
+
+export RESTIC_REPOSITORY="$REPO_DIR"
+export RESTIC_PASSWORD_FILE="$PASSWORD_FILE"
+
+# ── Init repo if needed ───────────────────────────────────────────────────────
+
+if [[ ! -d "$REPO_DIR" ]]; then
+    echo "Initializing restic repository at $REPO_DIR …"
+    restic init
+fi
+
+# ── Backup ────────────────────────────────────────────────────────────────────
+
+echo "Backing up $SOURCE → $REPO_DIR"
+restic backup "$SOURCE" \
+    --exclude="**/sessions" \
+    --exclude="**/session_data" \
+    --tag "cortex-home"
+
+# ── Prune ─────────────────────────────────────────────────────────────────────
+
+restic forget \
+    --keep-daily   "$KEEP_DAILY" \
+    --keep-weekly  "$KEEP_WEEKLY" \
+    --keep-monthly "$KEEP_MONTHLY" \
+    --tag "cortex-home" \
+    --prune
+
+echo "Backup complete."
+restic snapshots --tag cortex-home --last 3
diff --git a/install.py b/install.py
index 2a9f92d..1e1adf0 100755
--- a/install.py
+++ b/install.py
@@ -32,6 +32,10 @@ SERVICE_FILE = Path.home() / ".config" / "systemd" / "user" / f"{SERVICE_NAME}.s
 CLAUDE_CREDS = Path.home() / ".claude" / ".credentials.json"
 GEMINI_CREDS = Path.home() / ".gemini" / "oauth_creds.json"
 
+BACKUP_SCRIPT    = PROJECT_ROOT / "backup.sh"
+BACKUP_SVC_FILE  = Path.home() / ".config" / "systemd" / "user" / "cortex-backup.service"
+BACKUP_TMR_FILE  = Path.home() / ".config" / "systemd" / "user" / "cortex-backup.timer"
+
 # ── ANSI helpers ──────────────────────────────────────────────────────────────
 
 RESET  = "\033[0m"
@@ -252,6 +256,72 @@ def check_cli_auth():
         warn("  (completes an OAuth flow in your browser)")
 
 
+def setup_backup_timer(dry_run=False):
+    header("Backup (restic systemd timer)")
+
+    code, _, _ = run_quiet(["which", "restic"])
+    if code != 0:
+        warn("restic not found — skipping backup timer setup")
+        warn("  Install with: sudo pacman -S restic  (or your distro's package manager)")
+        return
+
+    ok("restic found")
+
+    svc_content = f"""\
+[Unit]
+Description=Cortex home backup (restic)
+After=network.target
+
+[Service]
+Type=oneshot
+ExecStart={BACKUP_SCRIPT}
+"""
+
+    tmr_content = """\
+[Unit]
+Description=Cortex home backup — daily at 03:00
+
+[Timer]
+OnCalendar=*-*-* 03:00:00
+Persistent=true
+
+[Install]
+WantedBy=timers.target
+"""
+
+    if dry_run:
+        if BACKUP_SVC_FILE.exists() and BACKUP_TMR_FILE.exists():
+            ok(f"Timer already installed")
+            code2, out, _ = run_quiet(["systemctl", "--user", "is-enabled",
+                                       "cortex-backup.timer"])
+            ok(f"Timer enabled: {code2 == 0}")
+        else:
+            warn("Backup timer not installed — would write service + timer units")
+        return
+
+    SERVICE_FILE.parent.mkdir(parents=True, exist_ok=True)
+
+    for path, content, label in [
+        (BACKUP_SVC_FILE, svc_content, "service"),
+        (BACKUP_TMR_FILE, tmr_content, "timer"),
+    ]:
+        existing = path.read_text() if path.exists() else ""
+        if existing == content:
+            ok(f"Backup {label} file unchanged")
+        else:
+            path.write_text(content)
+            ok(f"Backup {label} file written: {path}")
+
+    run(["systemctl", "--user", "daemon-reload"])
+    run(["systemctl", "--user", "enable", "--now", "cortex-backup.timer"])
+    ok("Backup timer enabled (daily 03:00)")
+
+    code2, out, _ = run_quiet(["systemctl", "--user", "list-timers",
+                                "cortex-backup.timer", "--no-pager"])
+    for line in out.splitlines()[:4]:
+        info(line)
+
+
 def print_status():
     header("Service status")
     code, out, _ = run_quiet(["systemctl", "--user", "status", SERVICE_NAME,
@@ -287,13 +357,18 @@ def main():
     if not dry:
         manage_service(dry_run=dry)
     check_cli_auth()
+    setup_backup_timer(dry_run=dry)
 
     if not dry:
         print_status()
 
     print(f"\n{BOLD}Done.{RESET}\n")
-    print("  Logs:    journalctl --user -u cortex -f")
-    print("  Swagger: http://localhost:8000/docs")
+    print("  Logs:      journalctl --user -u cortex -f")
+    print("  Swagger:   http://localhost:8000/docs")
+    print("  Backup:    ./backup.sh  (also runs daily at 03:00)")
+    print("  Snapshots: RESTIC_REPOSITORY=~/backups/cortex-home-restic \\")
+    print("             RESTIC_PASSWORD_FILE=~/.config/cortex/restic-password \\")
+    print("             restic snapshots")
     print()