We present the results of structural and magnetic phase comparisons of the iron oxychalcogenides La 2 O 2 Fe 2 OM 2 (M = S, Se). Elastic neutron scattering reveals that M = S and Se have similar nuclear structures at room and low temperatures. We find that both materials obtain antiferromagnetic ordering at a Neel temperature T N 90.1 ± 0.16 K and 107.2 ± 0.06 K for M = Se and S, respectively. The magnetic arrangements of M = S, Se are obtained through Rietveld refinement.We find the order parameter exponent β to be 0.129 ± 0.006 for M = Se and 0.133 ± 0.007 for M = S. Each of these values is near the Ising symmetry value of 1/8. This suggests that although lattice and electronic structural modifications result from chalcogen exchange, the nature of the magnetic interactions is similar in these materials.