| Election Name: | 1986 Colchester Borough Council election |
| Country: | Essex |
| Type: | parliamentary |
| Previous Election: | 1984 Colchester Borough Council election |
| Previous Year: | 1984 |
| Next Election: | 1987 Colchester Borough Council election |
| Next Year: | 1987 |
| Seats For Election: | 21 out of 60 seats to Colchester Borough Council |
| Majority Seats: | 31 |
| Turnout: | 41.6% (0.3%) |
| Party1: | Conservative Party (UK) |
| Last Election1: | 34 seats, 42.9% |
| Seats1: | 6 |
| Seats After1: | 28 |
| Seat Change1: | 6 |
| Popular Vote1: | 13,873 |
| Percentage1: | 33.3% |
| Swing1: | 9.6% |
| Party2: | SDP-Liberal Alliance |
| Last Election2: | 10 seats, 25.1% |
| Seats2: | 8 |
| Seats After2: | 16 |
| Seat Change2: | 6 |
| Popular Vote2: | 14,988 |
| Percentage2: | 36.0% |
| Swing2: | 10.9% |
| Party3: | Labour Party (UK) |
| Last Election3: | 12 seats, 28.2% |
| Seats3: | 5 |
| Seats After3: | 12 |
| Popular Vote3: | 11,185 |
| Percentage3: | 26.9% |
| Swing3: | 1.3% |
| Party4: | Tiptree Residents Association |
| Last Election4: | 3 seats, 2.3% |
| Seats4: | 1 |
| Seats After4: | 3 |
| Popular Vote4: | 1,110 |
| Percentage4: | 2.7% |
| Swing4: | 0.4% |
| Party5: | Independent politician |
| Last Election5: | 1 seat, 1.5% |
| Seats5: | 1 |
| Seats After5: | 1 |
| Popular Vote5: | 459 |
| Percentage5: | 1.1% |
| Swing5: | 0.4% |
| Council control | |
| Posttitle: | Council control after election |
| Before Election: | Conservative |
| After Election: | No overall control |
Elections to Colchester Borough Council were held on 8 May 1986 alongside other local elections across the United Kingdom.
At the election, the Conservative Party lost control of the council to no overall control after having held an overall majority since the 1976 election.
Vote share changes are compared to the top candidate result from the 1984 election.
Vote share changes are compared to the top candidate result from the 1984 election.
No Independent candidate as previous (-25.5).