AbstractChild sexual abuse (CSA) has serious short‐term and long‐term effects, including non‐suicidal self‐injury (NSSI) and suicidal ideation (SI). One possible thread linking CSA to NSSI and suicide risk is emotion dysregulation. The current study assessed whether facets of emotion dysregulation mediated relations of NSSI behaviours and functions, and SI. Participants (N = 121; Mean age = 18.69, age‐range 18–22; 78 per cent female), college students with a history of childhood trauma, completed an online survey. Results indicated that facets of emotion dysregulation (i.e. clarity, non‐acceptance) mediated the relationship between CSA and SI. CSA was associated with automatic negative reinforcement, social negative and social positive reinforcement NSSI functions, but was not associated with NSSI behaviours. Emotion dysregulation facets did not mediate the relationship between CSA and NSSI functions. Findings highlight the need to help CSA survivors have clarity and acceptance of emotional experiences to reduce SI risk.This research did not receive any specific grant from funding agencies in the public, commercial or not‐for‐profit sectors.