As remote learning technologies play an increasingly larger role in education, clear evidence of effectiveness is needed for widely used online learning technologies, such as Assessment and LEarning in Knowledge Spaces (ALEKS). By adapting to individual students' knowledge states and personalizing interactive practice and feedback, ALEKS may potentially support learning in mathematics, which is foundational for success in science, technology, engineering, and mathematics fields. Given the mixed findings about the effects of ALEKS in previous research, we conducted a meta-analysis to examine if ALEKS was as effective as traditional instruction in mathematics education. Our analysis included 56 independent effect sizes obtained from 9,238 students in K-12 schools and institutions of higher education participating in 33 research studies between 2000 and August 2020. Results indicated that learning performance with ALEKS was comparable to that with traditional instruction (Hedge's g = 0.05, 95% CI [-0.01, 0.20]) and ALEKS was especially effective when used to supplement traditional instruction (g = 0.43, 95% CI [0.02, 0.83]). These findings have important implications for using ALEKS in mathematics learning across different levels of education.