Background: Behavioral activation is recognized as a stand-alone, evidence-based therapy for depression. Internet-delivered psychological interventions are easy to access and low cost. Therefore, it is important to determine whether internet-delivered behavioral activation (iBA) is an effective option for improving depressive symptoms and other health-related outcomes. This systematic review and meta-analysis aimed to examine the effects of iBA on individuals with depressive symptoms. Methods: A comprehensive search was conducted within four databases to identify randomized controlled trials (RCTs) that involved iBA for people with depressive symptoms. The quality of the included RCTs was assessed using the Cochrane Collaboration risk-of-bias tool. Depending on I2 statistic values for heterogeneity, either a random effects model or fixed effects model was used. Subgroup analyses were conducted according to the type of control groups. Results: Twenty RCTs met the eligibility criteria. Meta-analyses showed iBA had small to medium effects on depressive symptoms, anxiety, quality of life, functioning, perceived social support, and behavioral activation (BA) in people suffering from depressive symptoms at the immediate posttest and follow-up compared to control conditions. Limitations: Relatively fewer studies were conducted to compare effects of iBA on outcomes other than depressive symptoms and BA process measures compared to comparison or control conditions. The overall risk of bias across the included RCTs was unclear. Conclusions: Further high-quality studies are needed to verify the effects of iBA on varied health outcomes and BA process measures for individuals with depressive symptoms.