Dato' Mahdzir bin Khalid (born 15 December 1960) is a Malaysian politician. He is the member of the Parliament of Malaysia for the seat of Padang Terap, Kedah, having been elected in the 2013 general election. He was the ninth Menteri Besar (Chief Minister) of the State of Kedah, from 2005 to 2008, and represented the seat of Pedu in the Kedah State Legislative Assembly from 2004 to 2013. He is a member of the United Malays National Organisation (UMNO) party in Malaysia's ruling Barisan Nasional coalition.
Mahdzir started his political career as a staffer and in 1999 became the political secretary to then deputy prime minister Abdullah Ahmad Badawi. In 2004 he was elected to the Kedah State Legislative Assembly for the rural seat of Pedu. In December of the following year he became the state's Chief Minister after his predecessor, Datuk Seri Syed Razak bin Syed Zain Barakhbah, resigned because of ill health. Mahdzir had been acting in the position since July.
Mahdzir's tenure as Menteri Besar came to an end after his Barisan Nasional government was defeated in the 2008 election by an opposition coalition led by the Pan-Malaysian Islamic Party (PAS). Mahdzir became Barisan Nasional's opposition leader in the state assembly, before moving to federal parliament in the 2013 election, winning the seat of Padang Terap from PAS.