Electoral district no. 3 (Estonian: Valimisringkond nr 3) is one of the 12 multi-member electoral districts of the Riigikogu, the national legislature of Estonia. The electoral district was established in 1995 following the re-organisation of the electoral districts in Tallinn. It is conterminous with the districts of Mustamäe and Nõmme in Tallinn. The district currently elects eight of the 101 members of the Riigikogu using the open party-list proportional representation electoral system. At the 2019 parliamentary election it had 71,882 registered electors.

Electoral district no. 3 currently elects eight of the 101 members of the Riigikogu using the open party-list proportional representation electoral system.^[3][4] The allocation of seats is carried out in three stages. In the first stage, any individual candidate, regardless of whether they are a party or independent candidate, who receives more votes than the district's simple quota (Hare quota: valid votes in district/number of seats allocated to district) is elected via a personal mandate.^[5] In the second stage, district mandates are allocated to parties by dividing their district votes by the district's simple quota.^[5] Only parties that reach the 5% national threshold compete for district mandates and any personal mandates won by the party are subtracted from the party's district mandates.^[5] Prior to 2003 if a party's surplus/remainder votes was equal to or greater than 75% of the district's simple quota it received one additional district mandate.^[5] Any unallocated district seats are added to a national pool of compensatory seats.^[5] In the final stage, compensatory mandates are calculated based on the national vote and using a modified D'Hondt method.^[5] Only parties that reach the 5% national threshold compete for compensatory seats and any personal and district mandates won by the party are subtracted from the party's compensatory mandates.^[5] Though calculated nationally, compensatory mandates are allocated at the district level.