2021 Altai Krai Legislative Assembly election

{{Context|date=September 2021}}

{{Infobox election

| election_name = 2021 Altai Krai Legislative Assembly election

| last_election3 = 8 seats, 21,01%

| leader1 = Sergey Shoygu

| candidate1 = Viktor Tomenko

| image1 = 100px

| election_date = 19 September 2021

| seats1 = 31

| next_year = 2026

| next_election = 2026 Altai Krai Legislative Assembly election

| previous_year = 2016

| previous_election = 2016 Altai Krai Legislative Assembly election

| ongoing = no

| type = legislative

| last_election1 = 42 seats, 34,08%

| seat_change1 = {{decrease}} 11 seats

| seat_change2 = {{decrease}} 5 seats

| country = Altai Krai

| party3 = CPRF

| leader3 = Gennady Zyuganov

| candidate3 = Maria Prusakova

| image3 =

| percentage2 =

| popular_vote2 =

| seats2 = 4

| popular_vote1 =

| last_election2 = 9 seats, 21,18%

| party2 = LDPR

| leader2 = Vladimir Zhirinovsky

| candidate2 = Vladimir Zhirinovsky

| image2 = 100px

| party1 = United Russia

| seats3 = 24

| seat_change4 = {{decrease}} 1 seat

| percentage3 =

| party5 = Yabloko

| leader5 = Nikolay Rybakov

| candidate5 = Alexander Goncharenko

| image5 =

| percentage4 =

| popular_vote4 =

| seats4 = 5 seats

| last_election5 = 0 seat, 3,13%

| last_election4 = 6 seats, 17,41%

| party4 = SRZP

| leader4 = Sergey Mironov

| candidate4 = Aleksandr Terentyev

| image4 = 100px

| seats5 = 0 seat

| popular_vote3 =

| seat_change3 = {{increase}} 16 seats

| seats6 = 4 seats

| percentage6 =

| popular_vote6 =

| seat_change6 = {{increase}} 4 seats

| last_election6 =

| seat_change5 =

| party6 = CPCR

| leader6 = Maxim Suraykin

| candidate6 = Maxim Suraykin

| image6 = 100px

| percentage5 =

| popular_vote5 =

| percentage1 =

}}

Altai Krai Legislative Assembly election was held in Altai Krai on 19 September 2021 along with State duma elections in Russia.

68 deputies are elected according to the mixed electoral system. 34 deputies are elected according to party lists (proportional representation) for which a 5% threshold is established, and the distribution of seats between lists that received more than 5% of the vote takes place according to the formula. The other 34 deputies are elected in single-mandate constituencies (plurality voting), won by the majority of votes. The term of office is five years.

As of July 1, 2021, 1 792 470 voters were registered in the Altai Krai.{{Cite web|title=Численность избирателей|url=http://www.altai-terr.izbirkom.ru/chislennost-izbirateley/?ELEMENT_ID=70440|access-date=2021-08-21|website=www.altai-terr.izbirkom.ru|archive-date=2021-08-18|archive-url=https://web.archive.org/web/20210818104111/http://www.altai-terr.izbirkom.ru/chislennost-izbirateley/?ELEMENT_ID=70440|url-status=dead}}