In this research, a meta-analysis study was conducted to determine the effect of student and teacher-centered practices in science lessons on students' scientific process skills. To this end, the literature related to the studies conducted in Turkey and abroad was searched. For this purpose, articles, master's, and doctoral theses published between 1999-2020 in national and international databases were scanned. As a result of the literature review, it was deemed appropriate to include a total of 100 studies in the meta-analysis. In the meta-analysis study, subgroup analysis was performed in the fields of science, publication year, education levels, sample size, application period and publication types. As a result of the meta-analysis, it was determined that student-centered practices had a positive effect on students' SPS in science lessons compared to teacher-centered ones. It was also found out that 93 of the 100 studies included in the study had a positive effect size and 7 had a negative effect size value. Of the positive studies, 6 were at the level of weak effect, 23 at the level of small effect, 21 at the level of medium effect, and 43 at the level of large effect. In light of the findings obtained, student-centered practices in science education appear to have a stronger effect on developing students' scientific process skills than teachercentered practices.