Stephen Campbell Mullighan (born ) is a former Australian politician who represented the South Australian House of Assembly seat of Lee for the Labor Party from 2014 to 2026. He served as the Treasurer of South Australia in the First Malinauskas ministry from 2022 to 2025.
Mullighan served as Minister for Transport and Infrastructure and Minister for Housing and Urban Development in the Weatherill Labor cabinet.
He previously held the portfolios of Minister assisting the Minister for Planning and Minister assisting the Minister for Housing and Urban Development. Mullighan entered cabinet in March 2014 and remained there until the March 2018 election when his party lost office. He has held ministerial portfolio with responsibility for transport and infrastructure, and for housing and urban development.
He is aligned with the Labor Right faction.