In this paper, the structure and magnetic behaviour of antiperovskite InxFe4-xN have been investigated systematically. The crystal lattice becomes larger and the Curie temperature decreases with increasing x. The magnetic state changes from a ferromagnetic to a glassy state. In addition, an obvious spin glass (SG) behaviour has been revealed in In0.6Fe3.4N (x = 0.6) with a freezing temperature of T0 = 73 K, dynamical exponent of zν = 5.51, and flipping time of τ0 = 4.26 × 10−11 s. The origin of the SG behaviour in In0.6Fe3.4N may be attributed to atomic disorders at Wyckoff position 1a or ferromagnetic frustrations, or the both.