Background Advances in breast cancer (BC) care have reduced mortality, but their impact on survival once diagnosed with metastasis is less well described. This systematic review aimed to describe population-level survival since 1995 for de novo metastatic BC (dnMBC) and recurrent MBC (rMBC).Methods We searched MEDLINE 01/01/1995−12/04/2021 to identify population-based cohort studies of MBC reporting overall (OS) or BC-specific survival (BCSS) over time. We appraised risk-of-bias and summarised survival descriptively for MBC diagnoses in 5-year periods from 1995 until 2014; and for age, hormone receptor and HER2 subgroups. FindingsWe identified 20 eligible studies (14 dnMBC, 1 rMBC, 5 combined). Potential sources of bias in these studies were confounding and shorter follow-up for the latest diagnosis period.