The proposed project involves a randomized controlled trial to test the feasibility, acceptability, and preliminary efficacy of a mHealth-enhanced PA intervention to increase daily bout-related (≥10-minute bouts) and total (≥1-minute bouts) moderate-intensity PA (MPA) and decrease daily SB in 70 non-physically impaired patients with ischemic stroke or TIA. After visiting the Weight Control Diabetes Research Center (WCDRC) and completing a baseline assessment that includes wearing a multi-sensor armband for 7 days to monitor daily MPA and SB, participants will be randomized to 12 weeks of either: mHealth-enhanced PA intervention (Tech-PAI; n=35) or a standard PA intervention (PAI; n=35), which will serve as an active control group. Participants assigned to Tech-PAI will receive 2 face-to-face goal-setting/counseling sessions (one at baseline to set individualized goals using data observed on the baseline armband monitor) for the first 6 weeks of the intervention and the other at the mid-intervention point (i.e. to evaluate progress and refine individualized goals), a fitness/activity tracker and access to the accompanying website to monitor and observe their progress towards set goals, weekly online skills training videos (during weeks 1-6) to help change PA and SB behaviors, and weekly e-mail feedback from research staff on their progress towards goals (during weeks 1-12). Participants assigned to PAI will also receive two face-to-face PA goal-setting counseling sessions, a pedometer, and printed materials to assist with recording and increasing MPA and steps. Participants in both groups will wear the multi-sensor armband monitor again for 7 days both at mid-intervention (end of week 6) and post-intervention (end of week 12). The Tech-PAI and PAI groups will be compared on changes in daily time spent in MPA and SB from baseline at mid- and post-intervention. At these same time points, the groups will be compared on changes in performance-based measures of cardiorespiratory/physical and cognitive function; questionnaire-based assessments of stroke-specific impact and quality of life and PA-related attitudes and beliefs; and blood pressure and inflammation (i.e. C-reactive protein levels collected via blood samples). Finally, the acceptability of the Tech-PAI will be examined as indicated by fitness tracker and related website usage patterns, completion of online skills training sessions, and participant satisfaction ratings.