The aim of this study is to understand using molecular dynamics (MD) simulations the dependence of the water contact angle on surfaces which consist of self-assembled monolayers with mixed terminal functionality. We have conducted all-atom MD simulations of pure water droplets spreading on mixed alkylthiol monolayers at room temperature. Each chain of the monolayer is terminated with either a hydroxyl or methyl group. A completely methyl-terminated monolayer gives a contact angle of 115 degrees whereas complete wetting is seen for the purely hydroxyl case. For the cases of partial coverage and uniform mixing of the chains, the simulation results for the water contact angle as a function of the surface composition agree with experimental data, but deviate from the Cassie prediction. The MD simulations provide a molecular scale picture of the contact line. We find that the contact line in these cases is far from circular. Instead, hydrogen-bonded chains or sheets of water extend from the base of the drop along pathways that are decorated with hydroxyl-terminated chains. A similar behavior is seen in a second set of simulations where domains of the same terminal functionality are patterned on the substrate at the same overall compositions as the simulations in the first set. We report the wetting kinetics, hydrogen-bonding structure, and equilibrium contact angle for each case studied.