Countess Sophie of Hainaut was a noblewoman from the County of Hainaut, a historical region in present-day Belgium. She was born in the late 13th century and became known for her influential role in the politics of her time, particularly through her marriage alliances. Sophie was married to Count John I of Hainaut, which strengthened ties between noble families. Her lineage played a significant role in the House of Avesnes, contributing to the political landscape of medieval Europe. Sophie's legacy is often associated with the power dynamics of the Low Countries during the 14th century.