I Riigikogu was the first legislature of the Estonian Parliament (Riigikogu). The legislature was elected after 1920 elections (held on 27–29 November 1920). It sat between 20 December 1920 and 30 May 1923, before the next round of elections were held.
The 1920 general election distributed the 100 seats as follows:
| Party | Seats | +/– | |
|---|---|---|---|
| Estonian Labour Party (ETE) | 22 | –8 | |
| Farmers' Assemblies (PK) | 21 | +13 | |
| Estonian Social Democratic Workers' Party (ESDTP) | 18 | –23 | |
| Estonian Independent Socialist Workers' Party (EISTP) | 11 | +4 | |
| Estonian People's Party (ER) | 10 | –15 | |
| Christian Democratic Party (KRE) | 7 | +2 | |
| Central Committee of Tallinn Trade Unions (TAK) | 5 | New | |
| German-Baltic Party (SBE) | 4 | +1 | |
| Russian National Union (VEE) | 1 | 0 | |
| Economic Group (MR) | 1 | New | |
| Total | 100 | –20 | |
| Source: Nohlen and Stöver[1] | |||
Chairmen:
First Assistant Chairman:
Second Assistant Chairmen:
Secretaries:
First Assistant Secretary
Second Assistant Secretary
See main article: Members of the 1st Riigikogu.