A terminal block marker designed to identify a terminal block. The terminal block marker includes a rigid base and a flexible film insert. The rigid base includes a top with a first arm having a first inwardly extending projection and a second arm having a second inwardly extending projection. The rigid base also includes a bottom with legs extending in a direction opposite the arms to hold the terminal block marker in the terminal block. A flexible film insert with identification markings is installed on the rigid base. The flexible film insert is positioned under a first projection of the first arm and rotated downward until the flexible film insert snaps under the second projection of the second arm. The first and second projections retain the flexible film insert on the rigid base to form the terminal block marker.