Best instructional methods are essential tools to bring desirable changes in pre-service science teachers. The available literature lacks enough meta-analytic review illustrating the effect of various instructional methods on pre-service science teachers' learning outcomes. This meta-analytic review identified instructional methods used for teaching pre-service science teachers the period from 2010 to 2020. A specific purpose of the study was to estimate their magnitude effect on pre-service science teacher's learning outcomes. This study was a meta-analytic review, whereby one hundred twelve (112) studies were selected from Google scholar, ERIC, and Science Direct. They were subjected to the screening process that removed twenty-six records like book chapters, conference abstracts, and duplicates. From eighty-six remained studies, inclusion criteria rejected sixty-one; thus, only twenty-five (25) of them reached the analysis stages and were reviewed. The data from each study were systematically analyzed, and a comprehensive meta-analysis was used to compute effect size according to Cohen's d. The effect level of twenty instructional methods on eighteen learning outcomes were identified. The 5E instructional model, argument-driven inquiry-based laboratory instruction, socio-scientific issues-based instruction, jigsaw method, instructional technology, and material design course, simulation-assisted laboratory instruction, argumentation-based instruction, field-based inquiry focused model of instruction, and documentary films-based instruction were determined to be the most effective than traditional methods. Their Cohen's d ranged from 0.8 to 2. Instructional methods with a moderate effect level like problem-based learning were identified. Implication for research and practice is the recommendation of their use for teaching pre-service science teachers based on their influencing ability. Instructional methods with very small effect (Cohen's d = 0.16) and small effect d = 0.2 were realized. Researchers are recommended to choose study designs and teaching contexts that allow an instructional method to prove its maximal effect. The study focused only on pre-service science teachers as participants. This calls for other meta-analyses to incorporate other domains of pre-service teacher's education.