Higher-order thinking skills (HOT) are expected to be skills needed now and in the future. Many learning strategies are applied to increase HOT. However, how effective is this in improving students' HOT abilities? This study will examine how effective learning is to improve HOT thinking skills. We use meta-analysis research techniques to analyze the research quantitatively. We have selected 21 articles from 60 Google Scholars that use models, media, and science learning assessments to improve HOT. Heterogeneity analysis (trim-fill, funnel plot approach, and Z value calculation) was used to prove the absence of publication bias. Forest plot analysis showed an average increase in learning effectiveness of 0.32 on the moderate effect. It shows that the effectiveness of learning is supported by strategies for using media, methods, and strategies for assessment. These factors are proven to increase the effectiveness of students' HOT abilities.