Cassandra Jane "Casey" Costello is a right-wing New Zealand politician, lobbyist and former police officer. She was elected to the New Zealand House of Representatives, representing the New Zealand First party, in the 2023 New Zealand general election. She was appointed Minister of Customs, Minister for Seniors and Associate Minister of Health in the Sixth National Government of New Zealand.

New Zealand First, commonly abbreviated to NZ First or NZF, is a political party in New Zealand, led by and identified with veteran politician Winston Peters, who has served three times as deputy prime minister. The party has formed coalition governments with both major political parties in New Zealand: with the New Zealand National Party from 1996 to 1998 and 2023 to present, and with the New Zealand Labour Party from 2005 to 2008 and 2017 to 2020. New Zealand First currently serves in a coalition government with both National and ACT as part of the Sixth National government, having won 6.08% of the total party vote in the 2023 New Zealand general election.