High blood pressure is a major risk factor for premature death. Leisure-time physical activities have been recommended to control hypertension. Studies examining how leisure-time physical activity affects blood pressure have found mixed results. We aimed to conduct a systematic review examining the effect of leisure-time physical activity (LTPA) on lowering blood pressure among adults living with hypertension. We searched studies in Embase, Medline/PubMed, Web of Science, Physical Education Index, Scopus and CENTRAL (the Cochrane Library). The primary outcome variables were systolic blood pressure (SBP) and diastolic blood pressure (DBP). This systematic review is registered on PROSPERO (CRD42021260751). We included 17 studies out of 12,046 screened articles in this review. Moderate-intensity LTPA (all types) reduced SBP compared to the non-intervention control group (MD −5.35 mm Hg, 95% CI −8.06 to −2.65, nine trials, n = 531, low certainty of the evidence). Mean DBP was reduced by −4.76 mm Hg (95% CI −8.35 to −1.17, nine trials, n = 531, low certainty of the evidence) in all types of LTPA (moderate intensity) group compared to the non-intervention control group. Leisure-time walking reduced mean SBP by −8.36 mmHg, 95% CI −13.39 to −3.32, three trials, n = 128, low certainty of the evidence). Walking during leisure time reduced −5.03 mmHg mean DBP, 95% CI −8.23 to −1.84, three trials, n = 128, low certainty of the evidence). Performing physical activity during free time probably reduces SBP and DBP (low certainty of the evidence) among adults with hypertension.