BACKGROUND: Dual-task gait training may improve dual-task gait speed after stroke, but the effects on the relative amount of dual-task interference are unclear. OBJECTIVE: To compare the efficacy of dual-task gait training (DTGT) and single-task gait training (STGT) on cognitive-motor dual-task interference after stroke. METHODS: 36 adults within 3 years of stroke were randomized 1:1 to STGT or DTGT, 3 times a week for 4 weeks. The primary outcomes were the relative dual-task effect on gait speed (DTEg, %) and cognitive task performance (DTEc, %) during walking at preferred and fast speed in two different dual-task conditions (auditory Stroop, auditory clock task). RESULTS: There were no treatment effects on DTEg or DTEc in either group for either dual-task at either walking speed. Across all participants, there were significant improvements in both single and dual-task gait speed in all conditions, without any relative change in the dual-task effect. Subgroup analysis suggested that those with greater interference at baseline may benefit more from DTGT. CONCLUSIONS: DTGT and STGT improved single and dual-task gait speed but did not change the amount of relative interference. The findings may be confounded by an unexpectedly small amount of gait-related dual-task interference at baseline.