The 240 members of the National Assembly are elected by open list proportional representation from 31 multi-member constituencies ranging in size from 4 to 16 seats.

[2] The incumbent government was a coalition between the conservative GERB party of Prime Minister Boyko Borisov and the nationalist United Patriots alliance (formed from IMRO, Attack and the NFSB), with the support of the populist Volya Movement.

During The Greens' 2020 national meeting, the party representatives voted in favor of a coalition at "the next parliamentary election with the other two members of Democratic Bulgaria".

[3] The deputy chairman of ITN, Toshko Yordanov, said in an interview for the Bulgarian National Radio, that the party "will not enter a coalition with GERB, DPS or BSP".

All lines with a light gray background indicate support for a party or coalition that has been agreed upon outside of the official CEC electoral registration.

[15] A central theme in the election was purported corruption in the GERB-led government, which saw GERB lose seats and various anti-corruption parties gain, most notably Slavi Trifonov's ITN, but also DB and ISMV.

[20] Korneliya Ninova of BSPzB formally received the final mandate from president Radev on 5 May 2021, but refused to form a government due to a lack of support from other parliamentary opposition parties.