| Election Name: | 1921 Woolwich East by-election |
| Type: | presidential |
| Country: | United Kingdom |
| Previous Election: | Woolwich East (UK Parliament constituency)#Elections in the 1910s |
| Previous Year: | 1918 |
| Next Election: | Woolwich East (UK Parliament constituency)#Elections in the 1920s |
| Next Year: | 1922 |
| Election Date: | 2 March 1921 |
| Candidate1: | Gee |
| Party1: | Unionist Party (UK) |
| Popular Vote1: | 13,724 |
| Percentage1: | 51.3 |
| Candidate2: | MacDonald |
| Party2: | Labour Party (UK) |
| Popular Vote2: | 13,041 |
| Percentage2: | 48.7 |
| Map Size: | 250px |
| MP | |
| Posttitle: | Subsequent MP |
| Before Election: | Crooks |
| Before Party: | Labour Party (UK) |
| After Election: | Gee |
| After Party: | Unionist Party (UK) |
The 1921 Woolwich East by-election was a parliamentary by-election held on 2 March 1921 for the British House of Commons constituency of Woolwich East, in the Metropolitan Borough of Woolwich in London.
The seat had become vacant on the resignation of the constituency's Labour Member of Parliament (MP), Will Crooks, due to ill-health. Crooks was a noted trade unionist and working-class organiser, and had represented Woolwich East and its predecessor seat, Woolwich, since a by-election in 1903, with a gap between the two general elections of 1910.
The newly formed Communist Party of Great Britain urged voters to abstain, saying ""that while the coalition candidate stands openly and avowedly for capitalism in all its ramifications, its industrial autocracy, its attacks on trade unions, its exploitation, its predatory imperialism, the Labour candidate stands for Capitalism and all its manifestations, none the less surely because its purpose is hidden under high sounding words".[1]
Gee took the seat with a majority of nearly 700 votes.
Gee held the seat until the 1922 election, when Harry Snell retook the seat for Labour.MacDonald would go on to be elected MP for Aberavon in 1922, and be re-elected Leader of the Labour Party, then become Prime Minister after the 1923 election.
Ramsay MacDonald campaigning at Woolwich