The dependence of carrier effectivemass of GaNxAs1 - x, InNxP1 - x, InNxAs1 - x, and InNxSb1 - x alloys on nitrogen content is investigated using a 10-band k.p model. The electron effective mass me. at the bottom of conduction band in GaNxAs1 - x and InNxP1 - x exhibits a gradual increase as a function of N concentration in the range 0-1% and a decrease of x value between 1 and 5%. However, the behavior of m(e)*. in InNxAs1 - x and InNxSb1 - x shows a strong decrease in all studied x-range. Our results are compared to the available data reported in the literature. On the other hand, contrary to heavy-hole effective mass m(hh)*, the light-hole effective mass m(lh)* in all studied alloys is significantly affected by nitrogen states, which modify the non-parabolicity of the LH band. The modification of the carrier effective mass affects the transport properties of the III-N-V alloys. (C) 2016 Elsevier B.V. All rights reserved.