Background: During the COVID-19 pandemic, the nature of communication has changed dramatically owing to lockdowns and the need for social distancing with ongoing outbreaks. As a result, patient's help-seeking behavior for mental health may have changed. We summarized the research on help-seeking behavior for mental health during the COVID-19 pandemic and investigated changes that have occurred. Methods: This study was a systematic review. We searched four literature databases: MEDLINE, EMBASE, CHI-NAHL, and PsycINFO. We included the following in the review: 1) studies conducted during the COVID-19 pandemic, and 2) studies that dealt with help-seeking behavior for mental health. Eligible studies were sum-marized according to characteristics such as research participants and study type. Results: In total, 41 studies (38 observational studies 2 qualitative studies and 1 randomized trial) were eligible for the review. Most studies reported delays, decreases, or deficits in help-seeking behavior. The study partici-pants included medical professionals, local residents, hospitals, children and adolescents, online participants, pregnant women, people who experienced intimate partner violence, those with eating disorders, and other individuals. Limitations: Findings from observational studies may have bias as confounder. Meta-analysis could not be per-formed, because the studies had variations of design. Conclusion: During the COVID-19 pandemic, delay in seeking help from mental health services may have resulted in lost opportunities to link patients with appropriate treatment and care. The COVID-19 pandemic is ongoing as of 2022. Therefore, it is important to examine the impact of the pandemic on mental health in future research.