John W. Aldag[1] (born April 18, 1963) is a Canadian politician who represented the riding of Cloverdale—Langley City in the House of Commons of Canada as a Liberal MP from 2015 to 2019 and 2021 to 2024.

[3] Aldag announced he would resign his seat effective May 27, 2024, to seek the BC New Democratic Party nomination in Langley-Abbotsford in the 2024 British Columbia election.

[8] Aldag took an unpaid leave from Parks Canada in December 2013 to begin campaigning for election to office, which he ultimately won with nearly 46% of the vote.

Aldag and his wife, Elaine St. John, a doctor, have two daughters and one son, and had lived in Langley for a decade at the time of his election to the House of Commons.

Aldag introduced Private Member's Bill C-374 which, if adopted, would provide a seat on the Historic Sites and Monuments Board of Canada for First Nations, Inuit and Métis representation.