A three-part referendum was held in Poland on 6 September 2015.^[1] Voters were asked whether they approved of introducing single-member constituencies for Sejm elections, maintaining state financing of political parties and introducing a presumption in favour of the taxpayer in disputes over the tax law.^[2]

The voter turnout of 7.80 percent was well below the 50-percent threshold required for the referendum results to be legally binding.^[3]

The referendums were ordered by President Bronisław Komorowski, who had promised to hold a referendum on the electoral system after the first round of the presidential elections,^[4] Although he had been leading in the polls, Komorowski received fewer votes (33.77%) than his main opponent Andrzej Duda (34.76%) in the first round. However third-placed candidate Paweł Kukiz received 20.8% of the vote, campaigning on introducing single-member constituencies for Sejm elections.^[5] A day after the May elections, Komorowski made an instantaneous decision to hold the referendum. Justifying his initiative, he explained that he saw high support for Kukiz as a signal that voters wanted changes.

The referendum asked voters the following three yes-or-no questions:

1. Are you in favour of introducing single-member constituencies in elections to the Sejm of the Republic of Poland?^{[lower-alpha 1]}
2. Are you in favour of maintaining the current method of financing of political parties from the national budget?^{[lower-alpha 2]}
3. Are you in favour of introducing a general rule of resolving doubts regarding the interpretation of taxation law in favour of the tax-payer?^{[lower-alpha 3][2]}