| Election Name: | 2012 Arumeru East by-election |
| Country: | Tanzania |
| Type: | by-election |
| Vote Type: | Popular |
| Ongoing: | no |
| Previous Election: | 2010 Tanzanian general election |
| Previous Year: | 2010 |
| Next Election: | Tanzanian general election, 2015 |
| Next Year: | 2015 |
| Needed Votes: | Simple-majority |
| Seats For Election: | The Arumeru East constituency in the Tanzanian Parliament |
| Turnout: | 60,699 (47.64%) |
| Colour1: | F33 |
| Party1: | Chadema |
| Popular Vote1: | 32,972 |
| Percentage1: | 54.92 |
| Candidate2: | Siyoi Sumari |
| Party2: | Chama Cha Mapinduzi |
| Popular Vote2: | 26,757 |
| Percentage2: | 44.57 |
| MP | |
| Before Election: | Jeremiah Sumari |
| Before Party: | Chama Cha Mapinduzi |
| After Election: | Joshua Nassari |
| After Party: | Chadema |
The Arumeru East by-election was a by-election held for the Tanzanian parliamentary constituency of Arumeru East. It was triggered by the death of Jeremiah Sumari, the previous Member of Parliament (MP) who had held the seat for the Chama Cha Mapinduzi since 2005.[1] The by-election took place on 1 April 2012 and the Chadema candidate won by 54.92%.[2]