This study examines the effects of problem-based learning (PBL) on students' academic achievement and higher-order thinking abilities through a systematic review of existing literature in Taiwan. A meta-analysis of 67 studies (45 studies for the academic achievement, and 31 for higher-order thinking abilities) indicated statistically significant positive effects of PBL on academic achievement (ES = 0.41) and higher-order thinking abilities (ES = 0.70). In addition, two moderator variables (i.e., subject area and during of treatment) selected for examining students' academic achievement, and seven moderator variables (i.e., grade level, subject area, type of PBL, digital platform and instructional materials, during of treatment, method of evaluation, and type of ability) selected for examining students' higher-order thinking abilities had a statistically significant impact on the mean ES.