Objective The COVID-19 pandemic brought global disruption, increased mortality, and concern about mental health impacts. Although children and young people (CYP) generally experienced less severe physical symptoms, public health measures such as school closures and restricted social interactions likely had adverse effects. Concerns were raised that risks of suicide and self-harm could increase during and after the pandemic. This review examined the extent to which these concerns were reflected in published evidence. Design A systematic search of databases was conducted for quantitative observational studies reporting suicide deaths, self-harm (including non-suicidal self-injury and suicide attempts), or suicidal ideation in individuals aged 24 years and under. Studies published between 1 January 2020 and 30 June 2022 were included. Quality was assessed using National Institutes of Health tools. Due to methodological heterogeneity, findings were synthesised narratively. Results Eighty-seven studies met inclusion criteria: 23 reported on suicide, 53 on self-harm, and 27 on suicidal ideation. Two were not peer-reviewed; all were observational. Most were conducted in healthcare settings and presented pre- and post-pandemic data. Half were rated low quality. Suicide data, largely from high-income countries, showed little or no overall change, though some studies reported increases among males. Moderate- or high-quality studies of self-harm indicated increases, especially from late 2020 into 2021/2022, and more pronounced among females. Increases in suicidal ideation were also reported, mainly in cohort or healthcare-based studies, though most were low quality. Conclusions The pandemic appeared to have minimal immediate impact on suicide rates in CYP. There was limited evidence from low- and middle-income countries, ethnic minorities, low-income households, and marginalised groups. Evidence of increased self-harm, particularly among females, highlights the need for age- and gender-specific policies, care pathways, and prevention strategies that are adaptable during future public health crises and ensure timely access to effective support. PROSPERO registration number: CRD42020183326 22 nd October 2020