One way to increase students' participation in science, technology, engineering, and mathematics (STEM) fields is to target their motivation. Researchers have conducted a growing number of interventions addressing students' motivation in STEM; however, this body of work has not been adequately reviewed. We systematically reviewed experimental and quasi-experimental studies (n = 53) targeting adolescent students' motivation for STEM subjects. While some interventions showed positive effects on a variety of motivational constructs and academic outcomes, others showed mixed or non-significant effects. We recommend that researchers more frequently examine moderating variables that might limit interventions' results, including individual-level variables such as gender, contextual-level variables such as the subject in which an intervention was conducted, and design-level variables such as intervention length. Additionally, researchers might better align their interventions with motivation theory. Future research should address these limitations so that the results of successful interventions can better inform educational policy and practice.