Background— Cardiovascular disease is the leading cause of death among women in high-income Organization for Economic Co-operation and Development countries. Physical activity is protective for cardiovascular disease. The realities of modern life require working-age women to address work-related, family, and social demands. Few working-age women meet current moderate-to-vigorous–intensity physical activity (MVPA) recommendations. Given that working-age women spend a substantial proportion of their waking hours at work, places of employment may be an opportune and a controlled setting to implement programs, improving MVPA levels and enhancing cardiometabolic health. Methods and Results— Eight electronic databases were searched to identify all prospective cohort and experimental studies reporting an MVPA outcome of workplace interventions for working-age women (mean age, 18–65 years) in high-income Organization for Economic Co-operation and Development countries. Risk of bias was assessed using the Cochrane risk of bias tool; quality of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. A qualitative synthesis was performed for all studies, and meta-analyses were conducted where possible. Twenty-four studies met the inclusion criteria; 20 studies were included in the meta-analyses. Workplace interventions significantly increased minutes per week of metabolic equivalents (4 studies; standardized mean differences, 2.07; 95% confidence interval [CI], 1.44 to 2.69), but not minutes per week of MVPA (13 studies; standardized mean differences, 0.38; 95% CI, −0.15 to 0.92) or metabolic equivalents per week (3 studies; standardized mean differences, 0.11; 95% CI, −0.48 to 0.71). Workplace interventions also significantly decreased body mass (7 studies; mean differences, −0.83 kg; 95% CI, −1.64 to −0.02), body mass index (6 studies; mean differences, −0.35 kg/m ² ; 95% CI, −0.62 to −0.07), low-density lipoprotein (4 studies; mean differences, −0.11 mmol/L; 95% CI, −0.17 to −0.04), and blood glucose (2 studies; mean differences, −0.18 mmol/L; 95% CI, −0.29 to −0.07). These workplace interventions targeting MVPA levels and known beneficial cardiometabolic health sequelae were of lower quality evidence. Conclusions— Workplace interventions variably improve MVPA levels and related cardiometabolic health sequelae of working-age women in high-income Organization for Economic Co-operation and Development countries. Our findings underscore the need for ongoing research in this area but also increased dissemination of the existing programs and knowledge.