The purpose of this research is to synthesize the results of experimental studies which investigated the effect of certain contemporary learning approaches including cooperative learning, multiple intelligence-based learning, problem-based learning, and constructivist learning approach on students' mathematics achievement via meta-analysis method. In order to collect the data, first the inclusion criteria were determined and a coding form was developed. As a result, the meta-analysis involved 47 experimental studies published between 2005 and 2014, which investigated the impact of contemporary learning approaches on learners' mathematics achievement. Based on the findings obtained from 2627 subjects who took part in these studies, a synthesis was done about the impact of contemporary learning approaches on mathematics achievement. The analysis based on the random effects model revealed that using contemporary learning approaches have a significant (p< 0.001) impact on mathematics achievement with a large effect size (d=0.93). This finding suggests that using contemporary learning approaches in mathematics lessons is effective in increasing the learners' mathematics achievement. As a result of the comparisons of common effect sizes between the groups based on random effects model, no statistically significant difference was observed between the specific learning approaches (Q(BG)=6.456, df=3, p=.091) and the school stages (Q(BG)=4.136, df=2, p=.126). Moreover, the meta-regression analysis based on random effects model revealed no statistically significant effect of the duration of treatment on learners' mathematics achievement in the lessons conducted in accordance with the contemporary learning approaches (z=-0.04990, p>.05). However, it was found that group size had a significant negative effect on mathematics achievement in the lessons conducted in accordance with the contemporary learning approaches (z=-2.12076, p<.05), i.e. as the number of students decreases, the better results are achieved from contemporary learning approaches in terms of learners' math achievement.