Purpose: Gait is a complex task that requires the interaction between motor and cognitive demand, being usually assessed using the dual-task (DT) paradigm. The aim of this study was to identify the effect of 21 weeks of application of multicomponent DT training on the spatiotemporal gait parameters, coefficients of variation, and DT cost in people with intellectual disability. Methods: A controlled longitudinal pre–post design with random assignment to two groups (experimental and control) was used. Fifty-seven participants with intellectual disability joined in this study (age: 39 ± 9 years). The OptoGait system was used to register spatiotemporal gait parameters in two different conditions: single task and DT. Results: The main findings revealed that in both conditions, the multicomponent DT training significantly reduced the coefficients of variation of spatiotemporal gait parameters (p < .001), whereas there was no effect on DT cost. Conclusions: These findings suggest that the multicomponent DT training elicited a more stable and confident gait pattern.