The　majority　of　visible-light　photocatalysts　show　very　low　hydrogen　evolution　activity　in　the　absence　of　noble　metal　co-catalysts　due　to　their　fast　carrier　recombination　rate.　Metallic　interstitial　nitrides　have　been　recognized　as　excellent　hydrogen　evolution　electrocatalysts　and　therefore　are　promising　alternative　co-catalysts　for　photocatalytic　hydrogen　production.　Herein　we　report　a　low-cost,　efficient,　noble-metal-free　visible-light-driven　hydrogen　evolution　photocatalyst　composed　of　Ni3N/g-C3N4　heterostructures.　The　as-prepared　photocatalyst　with　a　Ni3N　loading　content　of　3　wt%　shows　a　high　hydrogen　evolution　rate　of　169　μmol　g−1　h−1,　which　is　slightly　higher　than　that　of　3　wt%　Pt　modified　g-C3N4　(152.0　μmol　g−1　h−1).　The　Ni3N/g-C3N4　photocatalysts　also　exhibit　remarkable　photostability　for　four　consecutive　cycles　of　photocatalytic　activity　tests　with　a　total　reaction　time　of　12　hours.　The　excellent　performance　of　the　Ni3N/g-C3N4　photocatalyst　is　ascribed　to　the　formation　of　an　optimal　number　of　Ni3N/g-C3N4　heterojunctions　that　improve　photogenerated　carrier　separation　and　offer　abundant　photocatalytically　active　sites　for　surface　reactions.　©　The　Royal　Society　of　Chemistry.