Burkitt lymphoma (BL) is an aggressive mature B‐cell non‐Hodgkin lymphoma (B‐NHL) which consists of three subtypes: sporadic BL (sBL), endemic BL (eBL) and immuno‐deficiency related BL. Over 90% of children diagnosed with sBL in high‐income countries are successfully treated by current high‐intensity protocols. However, such intensive regimens are undeliverable in less well‐resourced settings. There is a need to identify markers to stratify low‐ and high‐risk patients and identify new therapeutic strategies. We have identified recurrent activating mutations of the transcription factor FOXO1 in both eBL and sBL. Similar mutations have been associated with poor outcome in diffuse large B cell lymphoma in adults, however the importance of FOXO1 has not been investigated in BL.