The aim of this systematic review was to summarize the literature on the associations between breaks in sitting time and cardiovascular health, in children and adolescents. The search was conducted using five databases (MEDLINE, SCOPUS, WEB OF SCIENCE, PSYCINFO and CINAHL) through to 01 October 2019. Due to heterogeneity of the data, meta-analyses were not possible. We screened 2577 studies, and 15 studies were included, representing 9116 participants, from six different countries. Five observational studies and four experimental studies showed associations between breaks in sitting time and cardiovascular health, i.e. an increased number of breaks in sitting time was negatively associated with a cardiovascular health outcome. No associations between number of breaks in sitting time and cardiovascular health outcomes were found in the six remaining studies. Studies examining associations between breaks in sitting time and cardiovascular health in children have shown some favorable associations. More epidemiological evidence is required, to inform lifestyle interventions and public health policies, which could translate into long-term implications on population health.