Organic photochemical reactions conducted in micellar solutions are reviewed from the standpoint of systematizing and correlating published results. Five common effects are found to distinguish and characterize micellar photochemistry relative to conventional solution photochemistry: “super” cage effects, local concentration effects, viscosity effects, polarity effects, and electrostatic effects. These effects can contribute to the occurence of enhanced selectivity and efficiency of photoreactions relative to those in conventional homogeneous solution.