Introduction: Emotion regulation difficulties have been associated with mental disorders and sexual dysfunctions. Traditional face-to-face transdiagnostic emotion regulation interventions have shown positive results for emotional and personality disorders. Only recently have the effects of these interventions on sexual health started to be investigated. Internet-delivered psychological interventions have several advantages over face-to-face interventions, such as cost-effectiveness, accessibility and suitability for people who experience shame because of their stigmatized problematic behaviors and those who avoid seeking help. The aims of the SHER 2 - TREpS (Portuguese acronym for Emotion Regulation training for sexual health) project are: a) determine the efficacy of an Internet-based emotion regulation intervention for sexual health and sexual satisfaction, and; b) explore the effects of the intervention on (1) emotion regulation skills; (2) mental health; (3) sexual self-perception. Methods and AnalysisThe study will use a randomized controlled trial design. Eligible participants will be randomly allocated to one of two groups: intervention (Internet-based emotion regulation training) or waitlist control. Assessments will take place before the start of the trial, at the end of the trial and at 6-month follow up, after which participants assigned to the waitlist control condition will receive the same intervention. Primary outcomes include sexual function and satisfaction, and secondary outcomes self-report measures of depression, anxiety, difficulties in emotion regulation, and sexual self-perception. This intervention study is financed by the Luxembourg National Research Fund (FNS). Ethics and dissemination: Ethics approval was obtained from the Ethics Review Panel of the University of Luxembourg. Findings will be disseminated via peer-reviewed publications and conference presentations.