Here, we investigate cosmological models with perfect fluid source in the framework of Kaluza-Klein FRW space time in a modified theory of gravity known as f (R, T) gravity (Harko et al. 2011) where R is the Ricci scalar and T is the trace of the stress energy tensor of the perfect fluid. By solving the field equations, we have found an exact solution of the field equations using a linearly varying deceleration parameter which can be considered as a five dimensional FRW type cosmological model in f (R, T) gravity. We have determined the spatial volume and average Hubble parameter of the model. We have also determined and discussed the physical parameters, pressure and density for dust, radiation and stiff matter dominated eras.