The flow of blood in the vasculature generates forces that act on vessel walls. Blood pressure generates circumferential stresses within the walls, while the endothelial lining of vessels experiences shear stresses as a consequence of blood’s motion over it. Both types of stress can elicit biological responses from cells in the walls, including growth and remodeling that are required for the normal function of the vasculature, and the development of vascular diseases. The main objective of this review is to summarize the dynamical features of blood flow as they affect the stresses that act on vessel walls. A second objective is to summarize the relationship between these stresses and the resulting structural responses in normal and disease states.