The photocatalytic hydrogen evolution performance of g-C3N4 was enhanced via the hybridization with montmorillonite (MMT) and using NiCoP as cocatalyst. The highest hydrogen-evolution rate from water splitting under visible-light irradiation observed over MMT/g-C3N4/15%NiCoP was 12.50 mmol g−1 h−1 under 1.0 mmol L−1 of Eosin Y-sensitization at pH of 11, which was ∼26.0 and 1.6 times higher than that of MMT/g-C3N4 (0.48 mmol g−1 h−1) and g-C3N4/15%NiCoP (7.69 mmol g−1 h−1). The apparent quantum yield at 420 nm reached 40.3%. The remarkably improved photocatalytic activity can be ascribed to the increased dispersion of g-C3N4 layers, staggered conduction band potentials between g-C3N4 and NiCoP, as well as the electrostatic repulsion originated from negatively charged MMT. This work demonstrates that MMT can be an outstanding support for the deposition of catalytically active components for photocatalytic hydrogen production.