Objective To appraise and synthesize evidence on the effects of health coaching as the primary intervention on cardiometabolic health among middle-aged adults. Data Source Six electronic databases (MEDLINE, Embase, PsycINFO, CINAHL, PubMed, and the Cochrane library) were searched from inception until July 2021. Study Inclusion and Exclusion Criteria Randomized controlled trials and controlled clinical trials published in English, reporting health coaching aimed to promote behavioral changes for improving cardiometabolic health among middle-aged adults were included. Studies on health coaching as secondary intervention were excluded. Data Extraction Two reviewers selected the articles, appraised the study quality, and extracted data independently. All kinds of outcomes related to cardiometabolic health, including health behaviors, psychological and physiological outcomes, were included. Data Synthesis Meta-analysis was performed if three or more studies reported the same outcomes. Narrative synthesis was performed if pooling of data for meta-analysis was not feasible. Results Eight studies were reviewed. Most studies involved substantial risk of bias. The majority of the participants were women (99.1%). Meta-analysis showed a small but significant effect of health coaching on increasing physical activity (SMD = .34, 95% CI = .08–.60, p = .01, I2 = 0%); however, its effect on perceived barriers to physical activity and depressive symptoms was nonsignificant. Narrative synthesis yielded inconsistent results on diet, smoking, anxiety, goal achievement and self-efficacy for behavioral change, physiological outcomes, and metabolic syndrome severity, and nonsignificant effects on alcohol consumption, sleep quality, perceived benefits of physical activities, and cardiovascular symptoms. Conclusions Health coaching has significant effects on increasing physical activity among middle-aged adults; however, its effects on health behaviors and risk factors related to cardiometabolic health are inconclusive. Further efforts are warranted to examine how health coaching can improve cardiometabolic health among middle-aged adults.