| Country: | San Marino |
| Flag Year: | 1862 |
| Type: | parliamentary |
| Previous Election: | 1974 |
| Next Election: | 1983 |
| Election Date: | 28 May 1978 |
| Seats For Election: | All 60 seats in the Grand and General Council |
| Majority Seats: | 31 |
| Turnout: | 78.98% (0.72pp) |
| Party1: | Sammarinese Christian Democratic Party |
| Last Election1: | 25 |
| Seats1: | 26 |
| Percentage1: | 42.30 |
| Party2: | Sammarinese Communist Party |
| Last Election2: | 15 |
| Seats2: | 16 |
| Percentage2: | 25.14 |
| Party3: | Sammarinese Socialist Party |
| Last Election3: | 8 |
| Seats3: | 8 |
| Percentage3: | 13.77 |
| Party4: | PSU |
| Last Election4: | new |
| Seats4: | 7 |
| Percentage4: | 11.13 |
| Party5: | PDS |
| Last Election5: | new |
| Seats5: | 2 |
| Percentage5: | 4.17 |
| Leader6: | Bonelli Menetto |
| Party6: | Committee for the Defence of the Republic |
| Last Election6: | 1 |
| Seats6: | 1 |
| Percentage6: | 2.82 |
General elections were held in San Marino on 28 May 1978.[1] The Sammarinese Christian Democratic Party remained the largest party, winning 26 of the 60 seats in the Grand and General Council.[2] Following the elections the Sammarinese Communist Party formed a coalition with the Sammarinese Socialist Party and the Unitary Socialist Party.
Voters had to be citizens of San Marino and at least 24 years old.