The next legislative election in Iran is scheduled for 21 February 2020, four years after the previous legislative election in 2016.
The 290-seat Islamic Consultative Assembly has 285 directly elected members and five seats reserved for the Zoroastrians, Jews, Assyrian and Chaldean Christians and Armenians (one for Armenians in the north of Iran and one for Armenians in the south).
The 285 directly elected seats are elected from 196 constituencies, which are a mix of single and multi-member. In single-member constituencies the leading candidates must receive at least one-fourth of the votes in the first round. If no candidate passes this threshold, a second round is held with the two highest-vote candidates. In multi-member constituencies, voters cast as many votes as there are seats available; candidates must receive votes from at least one-fourth of the voters to be elected; if not all the seats are filled in the first round of voting, a second round is held with twice the number of candidates as there are seats to be filled (or all the original candidates if there are fewer than double the number of seats).
Voters must be Iranian citizens aged 18 or over, and shall not have been declared insane.
Sources and further reading:
Mass disqualification of candidates add to discontent in Iran
Iran’s 2020 Parliamentary Election