Background: Cardiovascular disease (CVD) is the leading cause of premature death and disability in Europe, accounting for four million deaths per year and costing the EU economy almost €196 billion annually. There is strong evidence to suggest that exercise-based secondary rehabilitation programmes can decrease the mortality risk and increase health among patients with CVD. Theory informed use of behaviour change techniques (BCTs) is important in the design of cardiac rehabilitation programmes aimed at changing cardiovascular risk factors. Electronic health (eHealth), is the use of information and communication technologies (ICT) for health. This emerging area of healthcare has the ability to enhance self-management of chronic disease through making healthcare more accessible, affordable and available to the public. However, evidence-based information on the use of BCTs in eHealth interventions is limited, and particularly so for individuals living with CVD. Aim: The aim of this systematic review was to assess the application BCTs in eHealth interventions designed to increase physical activity (PA) in CVD populations. Methods: Seven electronic databases EBSCOhost (MEDLINE, PsycINFO, Academic Search Complete, SPORTDiscus with Full Text, CINAHL Complete), Scopus and Web of Science (Core Collection) were searched. Two authors independently reviewed references using the software package Covidence. The reviewers met to resolve any discrepancies, with a third independent acting as arbitrator when required. Following this, data was extracted from the papers that met the inclusion criteria. Bias assessment of the studies was carried out using the Cochrane Collaboration’s risk of bias tool within Covidence, this was followed by a narrative synthesis. Results: From the 987 studies identified 14 were included in the review. An additional 9 studies were added following a hand search of review paper references. The average number of BCT’s used across the 23 studies was 7.2 (range 1 to 19). The top three most frequently used BCTs included; information about health consequences (78.3%), goal setting (behaviour) (73.9%) and self-monitoring of behaviour (47.8%). Conclusion: This systematic review is the first to investigate the use of BCTs in physical activity eHealth interventions specifically designed for people with CVD. This research will have clear implications for healthcare, policy and research by outlining the BCTs used in eHealth interventions for chronic illnesses, in particular CVD. Hence, providing clear foundations for further research and developments in the area.