Career decision-making self-efficacy is one of the key concepts in the social cognitive theory; thus, programs to develop it must be informed by the best available evidence. To this end, a meta-analysis was undertaken to determine the extent to which different career interventions affect university students' levels of career decision-making self-efficacy. The existing literature was first reviewed, and 20 studies were included in the analysis based on a set of specific criteria. The studies selected for the meta-analysis were (a) experimental or quasi-experimental research and had a control group or a group that could be considered a comparison group, (b) reported what could be conceived as effects of career interventions on career decision-making self-efficacy, (c) recruited university students as participants, and (d) were published in English. Effect sizes were calculated using the Comprehensive Meta-Analysis software, and the results showed that career interventions were associated with a large increase in university students' levels of career decision-making self-efficacy.