This paper presents the findings of a systematic review of guidelines on preventing heat illness in sports participants and officials. University library databases and Internet sources were searched for guidelines pertaining to community-based sports, and occupational health and safety, using a comprehensive list of search terms. Guidelines were included if they met the criteria of English language, full text and fully referenced, and dealt specifically with, or could be extrapolated to, prevention of heat illness in sports participants and officials. Guideline inclusion was evaluated by two independent reviewers, who also independently assessed guideline quality using the AGREE instrument. Common guideline themes were identified by synthesis and recommendations for each theme were extracted. A synthesis of recommendations for common themes was then undertaken. Thirteen eligible guidelines were included. Thirty-two guidelines were excluded, as they did not provide sufficient information on construction or references. The methodological quality of the included guidelines was variable. The evidence-base of the guidelines varied, reflecting primary and secondary research. While five common heat-illness prevention themes were identified (fluid intake, heat limits, clothing, acclimatisation, precautionary interventions), variable recommendations were made pertaining to these themes. This potentially reflected the variable underpinning evidence of the guidelines. This review highlighted the need for better quality guideline construction related to defensible and transparent evidence sources regarding sports participation in hot weather. The synthesised recommendations cautiously provide a framework of current best evidence upon which sporting organisations internationally can base strategies for safe participation in the heat.