Risk-reducing salpingo-oophorectomy (RRSO) is the gold standard method of ovarian cancer risk reduction, but the data are conflicting regarding the impact on breast cancer (BC) outcomes. This study aimed to quantify BC risk/mortality in / carriers after RRSO. We conducted a systematic review (CRD42018077613) of / carriers undergoing RRSO, with the outcomes including primary BC (PBC), contralateral BC (CBC) and BC-specific mortality (BCSM) using a fixed-effects meta-analysis, with subgroup analyses stratified by mutation and menopause status. RRSO was not associated with a significant reduction in the PBC risk (RR = 0.84, 95%CI: 0.59-1.21) or CBC risk (RR = 0.95, 95%CI: 0.65-1.39) in and carriers combined but was associated with reduced BC-specific mortality in BC-affected and carriers combined (RR = 0.26, 95%CI: 0.18-0.39). Subgroup analyses showed that RRSO was not associated with a reduction in the PBC risk (RR = 0.89, 95%CI: 0.68-1.17) or CBC risk (RR = 0.85, 95%CI: 0.59-1.24) in carriers nor a reduction in the CBC risk in carriers (RR = 0.35, 95%CI: 0.07-1.74) but was associated with a reduction in the PBC risk in carriers (RR = 0.63, 95%CI: 0.41-0.97) and BCSM in BC-affected carriers (RR = 0.46, 95%CI: 0.30-0.70). The mean NNT = 20.6 RRSOs to prevent one PBC death in carriers, while 5.6 and 14.2 RRSOs may prevent one BC death in BC-affected and carriers combined and carriers, respectively. RRSO was not associated with PBC or CBC risk reduction in and carriers combined but was associated with improved BC survival in BC-affected and carriers combined and carriers and a reduced PBC risk in carriers.