Market response models help managers understand how customers collectively respond to marketing activities, and how competitors interact. When appropriately estimated, market response models can be a basis for improved marketing decision-making. Market response models can be broadly classified as: (a) those directly linking marketing stimuli or more generally relevant inputs to market response outputs; and (b) those that also model a mediating process. Inputs include marketing instruments (i.e., marketing mix variables) and environmental variables. This monograph takes a forward-looking perspective, including trends, to identify research opportunities related to market response and marketing mix models as falling under four broad areas: (1) "New" or under-studied inputs and/or "richer" measures of inputs constructs; (2) Explicitly accounting for the process linking inputs to outputs; (3) "New" or under-studied dependent variables; and (4) Under-studied or emerging contexts.