Kenneth Lex Shirley (born 12 August 1950), generally called Ken Shirley, is a former New Zealand politician. He was a member of the ACT New Zealand party, although was previously a member and Cabinet minister of the Labour Party.
Shirley first entered Parliament in the 1984 elections, when he stood as the Labour Party candidate in the Tasman electorate. At the time, there was considerable tension in the Labour Party over the policies of the Minister of Finance, Roger Douglas — the policies were based around economic deregulation and free trade, and traditionalists saw them as a betrayal of the party's left-wing roots. Shirley aligned himself with the faction that supported Douglas. Shirley was not a member of the faction's so-called "Troika" (consisting of Douglas, Richard Prebble, and David Caygill), but was nevertheless a notable supporter of the reforms Douglas promoted.
Eventually, the Prime Minister, David Lange, fired Douglas as finance minister and then himself resigned. In the re-arrangement that followed, Shirley briefly held Cabinet rank as Minister of Fisheries, Associate Minister of Agriculture, Associate Minister of Forestry, and Associate Minister of Health. He lost these positions when the Labour Party was defeated in the 1990 elections. Shirley himself lost his Tasman seat to National's Nick Smith, leaving him outside Parliament.