Aims: Produce an evidence-based ranking of the major contributing factors and sources of Campylobacter occurrence in broilers produced in England, Scotland and Wales - Great Britain (GB). Method and Results: Relevant data were extracted from 159 research papers and findings were grouped into 14 sources of on-farm contamination and 37 contributing factors. A relevancy score was developed to take into account various measures from each study of applicability to GB broilers and strength of findings. Results indicate that major sources of Campylobacter include a depopulation event, another house on-farm, on-farm staff, and other animals on farm. The depopulation schedule (staggered slaughter) and multiple houses on-farm were identified as contributing factors associated with increasing the risk, and those decreasing the risk were use of a hygiene barrier, parent company and certain seasons of rearing. Conclusions: Although the review was more resource intensive compared to narrative studies, the system allows an increased level of transparency and the ability to investigate patterns and trends. Significance and Impact of the Study: This paper provides the first evidence-based ranking of the major sources and contributing factors for Campylobacter presence in broilers in GB using a systematic review.