Background: Stroke frequently causes upper-extremity weakness that can restrict hand use and independence in daily activities. Repetitive hand exercise is a low-cost rehabilitation approach that may support motor recovery. Purpose: To compare short-term hand muscle strength between patients with stroke who received rubber ball gripping exercise plus standard hospital therapy and those who received standard hospital therapy alone. Method: This quasi-experimental two-group pretest-posttest study included 20 patients with stroke selected purposively from a population of 88 at Advent Hospital Bandar Lampung. Ten participants were included in each group. The intervention group performed rubber ball gripping exercise for 2 × 15 minutes per day for 3 consecutive days, while the control group received standard hospital therapy. Hand muscle strength was assessed using the Lovett scale (0–5), and posttest scores were compared using the Mann-Whitney U test. Results: Mean hand muscle strength in the intervention group increased from 3.20 ± 0.422 at pretest to 4.20 ± 0.422 at posttest, whereas the control-group mean remained 3.20 ± 0.422. Posttest hand muscle strength differed significantly between groups (p < 0.001). Conclusion: Rubber ball gripping exercise was associated with a greater short-term increase in hand muscle strength than standard hospital therapy alone in this small quasi-experimental sample. The findings should be interpreted cautiously because the group-assignment procedure, standard-care content, and longer-term outcomes were not fully reported.