Lower limb strength is a key factor in physical education and sports. This study examined the reliability and feasibility of the one-leg sit-to-stand test (OLSTST) as a functional assessment tool. The OLSTST uses only one leg to perform five sit-to-stand repetitions from a standard chair. Ninety-six healthy participants completed one testing session assessing dominant (preferred for tasks like kicking a ball) and non-dominant legs, with three trials per leg. Reliability was evaluated using intraclass correlation coefficients (ICC), standard error of measurement (SEM), and minimal detectable change (MDC). The OLSTST showed good test-retest reliability (ICC >0.83). SEM (0.30-0.46 s) reflected low measurement error, and MDC (0.84-1.28 s) indicated that small changes in performance can be confidently interpreted as real. A learning effect was observed, supporting a two-trial protocol. Feasibility was high (82.76%). The OLSTST is a practical, reliable tool for assessing unilateral lower limb strength in applied settings.