The co-processing of crude oil with green methanol offers a promising pathway for integrating renewable carbon into conventional refining, yet the presence of water or any hydrophilic components such as methanol can significantly influence catalyst performance, reaction selectivity, and overall process efficiency. We discuss experimental and kinetic modeling aspects of cofeeding water and methanol during crude oil catalytic cracking over a wide range of temperatures (525–650 °C) and catalyst-to-oil ratios (0–4.14) using a microactivity testing unit (MAT). During cofeeding, yields of gas and coke, and propylene-to-ethylene ratios fluctuated at low and high catalyst-to-oil ratios, respectively. Interestingly, cofeeding water and methanol lowered coke formation, while higher selectivity to light olefins over paraffins was observed in the presence of only water. Reparameterization of the kinetic model for Arabian light crude using water cofeeding data revealed changes in the intrinsic kinetic parameters of the cracking reactions. Specifically, the rate constant for the monomolecular cracking pathway leading to propylene increased across the entire temperature range, while the rate constants associated with condensation reactions, responsible for generating coke precursors, were reduced.