College students diagnosed with ADHD will be randomized to three arms of approximately 8 weeks duration: (1) standard care plus a tai chi class, (2) standard care plus an exercise class, and (3) standard care alone. The exercise class will control for the social and motor components of tai chi training. The investigators will determine methodological parameters relevant to a subsequent full scale trial including recruitment and retention rates, acceptance of randomization, adherence to the interventions, and variance in outcome measures. The primary clinical outcome measure of this pilot randomized controlled trial (RCT) will be pre- to post-intervention change in inattention, i.e. the Inattentive Symptoms subscale of the Conners Adult ADHD Rating Scale self-report long form (CAARS-S:L, see Interviews etc. "Converse_S_L"). Secondary measures to be explored will include self- and informant-report, neurocognitive measures, psychophysiological measures, and academic performance. Practice time will be assessed daily and follow-up self-report of ADHD symptoms will be gathered monthly for 3 months beyond the end of the intervention.