Aupito Tofae Su'a William Sio is a politician who became a member of the New Zealand House of Representatives on 1 April 2008 for the Labour Party as a list MP. From the November 2008 election to 2023, he represented the Māngere electorate.

The 2008 New Zealand general election was held on 8 November 2008 to determine the composition of the 49th New Zealand Parliament. The liberal-conservative National Party, headed by its parliamentary leader John Key, won the largest share of votes and seats, ending nine years of government by the social-democratic Labour Party, led by Helen Clark. Key announced a week later that he would lead a National minority government with confidence-and-supply support from the ACT, United Future and Māori parties. The Governor-General swore Key in as New Zealand's 38th Prime Minister on 19 November 2008. This marked the beginning of the Fifth National Government which governed for the next nine years, until the 2017 general election, when a government was formed between the Labour and New Zealand First parties, with support on confidence and supply by the Green Party.