2017 Turkish constitutional referendum "No" campaign

The 2017 Turkish constitutional referendum 'No' campaign (Turkish: Hayır) refers to a collection of unsuccessful political campaigns led by political parties, organizations and media outlets in favour of a 'No' vote in the 2017 Turkish constitutional referendum. Were the campaign to have been successful, it would have resulted in Turkey remaining a parliamentary republic as opposed to an executive presidency, which it became as a result of the referendum, and would have constituted the first direct upset against the governing Justice and Development Party (AKP) since they took office in 2002.

'No' campaigners faced alleged government-backed coercion and suppression. On 1 March, the main opposition Republican People's Party (CHP) unveiled a 78-point report regarding irregularities and suppression of 'No' campaigners, with Deputy Leader Öztürk Yılmaz claiming that those who were campaigning for a 'No' vote faced fear and state coercion. CHP parliamentary group leader Engin Altay also criticized the government for using state funds to fund the 'Yes' campaign while repressing 'No' voters, claiming that their conduct did not allow them to talk of 'democracy'.

A 'No' vote was supported by the main opposition party, CHP, and the smaller opposition Peoples' Democratic Party (HDP). Over 40 smaller political parties were also in favour of a 'No' vote, as well as a significant number of Nationalist Movement Party (MHP) politicians and voters who opposed their leader President Recep Tayyip Erdogan's call for a 'Yes' vote. The main rival to the 'No' campaign, which did not have a centralized or united structure, was the 'Yes' campaign.

The 'No' option on the ballot paper used for the referendum was coloured in a light brown.