This research study aims to utilize a second-order meta-analysis procedure to synthesize the effects of inquiry-based learning model (IBLM) on learning outcomes. An extensive systematic review process resulted in the inclusion of 10 meta-analyses conducted between 2015 and 2022 with minimal overlap between primary studies. The results revealed that IBLM has a medium-level positive effect (d=0.62) on learning outcomes. The analyses showed that mobile inquiry-based model, learning cycle model and conceptual change text model have high-level positive effect on learning outcomes. Moderator analyses revealed that the effect sizes were not significantly moderated by grade level, content area, location, quality, primary research report type, and publication bias. Limitations, educational implications, and directions for future research are provided.