Embedding online learning within higher education can provide engaging, cost-effective, interactive and flexible education. By evaluating the impact, outcomes and pedagogical influence of online cancer and education, future curricula can be shaped and delivered by higher education providers to better meet learner, health care provider and educational commissioners' requirements for enhanced patient care and service delivery needs. Using the Kirkpatrick's four-level model of educational evaluation, a systematic review of the effectiveness of online cancer education for nurses and allied health professionals was conducted. From 101 articles, 30 papers were included in the review. Educational theory is not always employed. There is an absence of longitudinal studies to examine impact; an absence of reliability and/or validity testing of measures, limited experimental designs taking account of power and few attempts to mitigate bias. There is, however, an emerging innovative use of mobile/spaced learning techniques. Evidence for clinical and educational effectiveness is weak offering insights into experiences and participant perceptions rather than concrete quantitative data and patient-reported outcomes. More pedagogical research is merited to inform effective evaluation of online cancer education, which incorporates and demonstrates a longer-term impact.