A geometric graph G is an a angle crossing (alpha AC) graph if every pair of crossing edges in G cross at an angle of at least alpha. The concept of right angle crossing (RAC) graphs alpha = pi/2) was recently introduced by Didimo et al. [10]. It was shown that any RAC graph with n vertices has at most 4n-10 edges and that there are infinitely many values of n for which there exists a RAC graph with n vertices and 4n-10 edges. In this paper, we give upper and lower bounds for the number of edges in alphaAC graphs for all 0 < alpha < pi/2.