Toilet training is a critical life skill that can be challenging for individuals with intellectual and developmental disabilities to acquire without additional support. This dissertation is composed of two studies. The first study is a systematic review of toilet training interventions for daytime urinary incontinence across home and school settings spanning 21 years. A review of the toilet training literature revealed variable primary outcomes, strong maintenance and generalization outcomes, and highly variable participant and intervention characteristics. The second study evaluated the effectiveness of a toilet training intervention on incontinence and self-initiated continent voids in three middle-aged children with IDD while also assessing for generalization effects across settings. Two out of three participants were successfully toilet trained, two out of three participants began to acquire the response to self-initiate bathroom trips, and treatment did not generalize across settings without additional intervention.