Objective: Although breast reconstruction has become an important treatment modality following mastectomy, few studies assessed predictors of postoperative sexual outcomes after breast reconstruction. Therefore, we aimed to study three sexual outcomes following implant-based breast reconstruction (IBBR), and associate multiple biopsychosocial factors with these outcomes. Methods: Data collection was part of a multicenter prospective study on IBBR. A predictive model was tested including medical, background and psychological predictors, partner relationship factors and physical sexual function. Data collection included clinical and questionnaire data (preoperatively and 1 year following reconstruction) using the BREAST-Q Sexual well-being scale (BQ5), and questions regarding sexual dysfunction and sexual satisfaction questions (Female Sexual Function Index). Results: The study sample consisted of 88 women who underwent mastectomy and IBBR. Mean postoperative BQ5 scores were lower than before surgery (M = 58 [SD = 18] vs 65 [SD = 20]; P =.01, Wilks' Lamdba =.88). Sexual dysfunctions were related strongest to orgasm inability and vaginal lubrication issues. The tested models predicted 37%-46% of the sexual outcomes: sexual outcomes were mostly predicted by psychosocial well-being, physical sexual function and partner support. Preoperative sexual and psychosocial well-being were positively associated with postoperative sexual well-being (r = 0.45 and r = 0.47). Conclusions: Although moderately positive sexual outcomes were reported after IBBR, some women reported issues with vaginal lubrication, breast sensation and orgasm. Sexual dysfunctions were predicted by vaginal lubrication and medical treatments, while sexual well-being and satisfaction were more predicted by psychosocial well-being and partner support. We advocate supportive care that includes partners and psychosocial functioning to optimize sexual outcomes after IBBR.