| Election Name: | 1977 Singaporean by-elections |
| Country: | Singapore |
| Flag Year: | 1977 |
| Flag Image: | Flag of Singapore.svg |
| Type: | parliamentary |
| Previous Election: | 1970 Singaporean by-elections |
| Previous Year: | 1970 |
| Next Election: | 1979 Singaporean by-elections |
| Next Year: | 1979 |
| Election Date: | 14 May 1977 (Radin Mas) 23 July 1977 (Bukit Merah) |
| Seats For Election: | 2 seats to the Parliament of Singapore |
| Registered: | 35,412 |
| Turnout: | 33,897 (95.72%) 1.27% |
| Image1: | Prime Minister Lee Kuan Yew of Singapore Making a Toast at a State Dinner Held in His Honor, 1975.jpg |
| Image1 Size: | 150x150px |
| Leader1: | Lee Kuan Yew |
| Party1: | People's Action Party |
| Seats1: | 2 |
| Popular Vote1: | 23,678 |
| Percentage1: | 71.38% |
| Swing1: | 4.62% |
| Image2 Size: | 150x150px |
| Leader2: | J. B. Jeyaretnam |
| Party2: | Workers' Party (Singapore) |
| Seats2: | 0 |
| Popular Vote2: | 5,021 |
| Percentage2: | 15.14% |
| Swing2: | 2.69% |
| Leader3: | Lee Siew Choh |
| Party3: | Barisan Sosialis |
| Seats3: | 0 |
| Popular Vote3: | 4,473 |
| Percentage3: | 13.48% |
| Swing3: | 13.48% |
| MPs | |
| Before Party: | PAP |
| Posttitle: | Elected MPs |
| After Party: | PAP |
There were 2 by elections held in 1977 where both People's Action Party's Members of Parliament, N. Govindasamy and Lim Guan Hoo had died suddenly, which vacates Radin Mas and Bukit Merah respectively. Through co-operation within the opposition camp, no 3 corner / multiple corner fights were shown in both by-elections.
With the demise of N. Govindasamy who was the then incumbent of Radin Mas, it sets the first by election in 1977 with the polling day on 14 May 1977 and the nomination day was set on 4 May 1977.
With the demise of Lim Guan Hoo who was the then incumbent of Bukit Merah, it sets the second by election in 1977 with the polling day on 23 July 1977 and the nomination day was set on 13 July 1977.
The election deposit was set at $1200. Similar with previous elections, the election deposit will be forfeited if the particular candidate had failed to secure at least 12.5% or one-eighth of the votes.