Breg may refer to:
Places Slovenia Breg, Majšperk, settlement in the Municipality of Majšperk Breg, Mežica, settlement in the Municipality of Mežica Breg, Sevnica, settlement in the Municipality of Sevnica Breg, Žirovnica, village in the Municipality of Žirovnica Breg ob Bistrici, settlement in the Municipality of Tržič
Serbia Bački Breg, village
Croatia Breg, Croatia, village in Istria County
River Breg (river), river in Germany
Names Breg (Irish mythology), considered a classic Celtic Triple Goddess Cobthach Cóel Breg, high king of Ireland in the 6th century BC
Science Regulatory B cells (Bregs)