Individuals with ADHD often show performance deficits in motor tasks. It is not clear, however, whether this reflects less effective acquisition of skill (procedural knowledge), or deficient consolidation into long-term memory, in ADHD. The aim of the study was to compare the acquisition of skilled motor performance, the expression of delayed--consolidation phase--gains and retention, in persons with and without ADHD. Thirty-two participants, 16 with ADHD, were trained on a sequence of finger movements using a well-established training protocol, and tested before training and immediately, 24 h and 2 weeks after training. Both groups showed similar within-session gains in speed; additional, delayed gains were expressed at 24 h, but less robustly in ADHD, and at 2 weeks post-training. However, while controls showed significant delayed gains in accuracy at 24 h and 2 weeks post-training, accuracy deteriorated in ADHD from pre-training to 24 h post-training and was only at pre-training levels by 2-weeks post-training. Our results demonstrate a latent memory consolidation phase in motor sequence learning, expressed as delayed gains in speed and a much delayed recovery of pre-training accuracy, in individuals with ADHD. However, both the acquisition and memory consolidation of motor skills are atypical in ADHD.