We define and characterize the γ-matrix associated with Pascal-like matrices that are defined by ordinary and exponential Riordan arrays. We also define and characterize the γ-matrix of the reversions of these triangles, in the case of ordinary Riordan arrays. We are led to the γ-matrices of a one-parameter family of generalized Narayana triangles. Thus these matrices generalize the matrix of γ-vectors of the associahedron. The principal tools used are the bivariate generating functions of the triangles and Jacobi continued fractions.