diff --git a/.gitleaks.toml b/.gitleaks.toml
new file mode 100644
index 00000000..9ecf1248
--- /dev/null
+++ b/.gitleaks.toml
@@ -0,0 +1,19 @@
+# This allow-list is limited to YAML/YML files to cut down SealedSecrets false positives.
+# All gitleaks default rules still apply everywhere (useDefault = true).
+# To broaden this allow-list to all files, comment out the 'paths' line below.
+
+[extend]
+useDefault = true
+
+[[rules]]
+id = "generic-api-key"
+
+# Pattern-only allowlist for long Ag… tokens in YAML 
+[[rules.allowlists]]
+condition = "AND"
+regexes = [
+  # Boundary-safe Ag… token without lookarounds (RE2-safe)
+  '''(?:^|[^A-Za-z0-9+/=])(Ag[A-Za-z0-9+/]{500,}={0,2})(?:[^A-Za-z0-9+/=]|$)'''
+]
+# Limit to YAML only for now. Comment this out if you want it to apply everywhere.
+paths = ['''(?i).*\.ya?ml$''']
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index ef75b79c..5b01b5a4 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -30,3 +30,8 @@ repos:
         language: system
         entry: uv sync
         files: ^(uv\.lock|pyproject\.toml)$
+
+  - repo: https://github.com/gitleaks/gitleaks
+    rev: v8.28.0
+    hooks:
+      - id: gitleaks
diff --git a/template/.gitleaks.toml b/template/.gitleaks.toml
new file mode 120000
index 00000000..3a6d50ec
--- /dev/null
+++ b/template/.gitleaks.toml
@@ -0,0 +1 @@
+../.gitleaks.toml
\ No newline at end of file
diff --git a/tests/test_gitleaks_precommit.py b/tests/test_gitleaks_precommit.py
new file mode 100644
index 00000000..43f9ce85
--- /dev/null
+++ b/tests/test_gitleaks_precommit.py
@@ -0,0 +1,129 @@
+from pathlib import Path
+
+import pytest
+
+from test_example import copy_project, make_venv
+
+# --- Stable patterns gitleaks flags out-of-the-box (should FAIL) ---
+STABLE_LEAK_CASES = [
+    ("github_token.txt", "ghp_1234567890abcdefghijklmnopqrstuvwx12AB"),
+    (
+        "slack_webhook.txt",
+        "https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX",
+    ),
+    ("stripe_secret.txt", "sk_test_4eC39HqLyjWDarjtT1zdp7dcFAKE"),
+]
+
+
+@pytest.mark.parametrize("fname, content", STABLE_LEAK_CASES)
+def test_gitleaks_stable_patterns_fail(tmp_path: Path, fname: str, content: str):
+    """
+    Generate a project, add a known-leaky pattern, stage it,
+    and verify tox -e pre-commit (gitleaks) fails.
+    """
+    copy_project(tmp_path)
+    run = make_venv(tmp_path)
+
+    (tmp_path / fname).write_text(content)
+    run("git add -A")  # pre-commit's gitleaks scans the staged index
+
+    with pytest.raises(AssertionError, match=r"(?i)(leak|gitleaks|secret)"):
+        run(".venv/bin/tox -e pre-commit")
+
+
+# --- Sealed-secrets: YAML/YML allowlisted; non-YAML should be flagged ---
+def _fake_sealed_secret_blob(n: int = 800, seed: str = "sealed-secrets-test") -> str:
+    """
+    Generate a deterministic, base64-looking ciphertext that resembles a SealedSecret.
+    - Always starts with 'Ag'
+    - Uses a realistic base64 alphabet mix (via sha256-derived bytes)
+    - Adds '=' padding only if required by base64 length
+    - Deterministic for stable tests (change `seed` to vary appearance)
+    """
+    import base64
+    import hashlib
+
+    # Build a deterministic byte stream from the seed, not random
+    chunk = hashlib.sha256(seed.encode("utf-8")).digest()  # 32 bytes
+    raw = (chunk * ((n // len(chunk)) + 4))[: n + 64]  # extra slack, then trim
+
+    # Base64-encode -> realistic distribution of A–Z a–z 0–9 + /
+    b64 = base64.b64encode(raw).decode("ascii")
+
+    # Compose with 'Ag' prefix and keep length near n
+    body = b64.replace("=", "")  # remove padding from the body
+    s = "Ag" + body[:n]  # ensure 'Ag' at start
+
+    # Fix padding so total length is a multiple of 4 (valid base64-looking)
+    rem = len(s) % 4
+    if rem:
+        s += "=" * (4 - rem)
+    return s
+
+
+def test_gitleaks_yaml_allowlist_for_sealed_secrets_yaml(tmp_path: Path):
+    """
+    Case 1: .yaml (allowlisted => PASS)
+    """
+    blob = _fake_sealed_secret_blob()
+
+    sealed_yaml = f"""\
+apiVersion: bitnami.com/v1alpha1
+kind: SealedSecret
+metadata:
+  name: demo
+  namespace: default
+spec:
+  encryptedData:
+    token: "{blob}"
+"""
+
+    proj_yaml = tmp_path / "proj_yaml"
+    proj_yaml.mkdir()
+    copy_project(proj_yaml)
+    run_yaml = make_venv(proj_yaml)
+    (proj_yaml / "secret.yaml").write_text(sealed_yaml)
+    run_yaml("git add -A")
+    run_yaml(".venv/bin/tox -e pre-commit")
+
+
+def test_gitleaks_yaml_allowlist_for_sealed_secrets_yml(tmp_path: Path):
+    """
+    Case 2: .yml (allowlisted => PASS)
+    """
+    blob = _fake_sealed_secret_blob()
+
+    sealed_yaml = f"""\
+apiVersion: bitnami.com/v1alpha1
+kind: SealedSecret
+metadata:
+  name: demo
+  namespace: default
+spec:
+  encryptedData:
+    token: "{blob}"
+"""
+
+    proj_yml = tmp_path / "proj_yml"
+    proj_yml.mkdir()
+    copy_project(proj_yml)
+    run_yml = make_venv(proj_yml)
+    (proj_yml / "secret.yml").write_text(sealed_yaml)
+    run_yml("git add -A")
+    run_yml(".venv/bin/tox -e pre-commit")
+
+
+def test_leaky_code_fails_gitleaks(tmp_path: Path):
+    """
+    Case 3: non-YAML (should be flagged => FAIL)
+    """
+    blob = _fake_sealed_secret_blob()
+
+    proj_code = tmp_path / "proj_code"
+    proj_code.mkdir()
+    copy_project(proj_code)
+    run_code = make_venv(proj_code)
+    (proj_code / "leaky.py").write_text(f'api_key = "{blob}"\n')
+    run_code("git add -A")
+    with pytest.raises(AssertionError, match=r"(?i)(leak|gitleaks|secret)"):
+        run_code(".venv/bin/tox -e pre-commit")