| Birth Date: | 6 March 1949 |
| Birth Place: | Amsterdam[1] |
| Theo Timmer | |
| Nationality: | Dutch |
| Gp Active Years: | 1972 - 1987 |
| Gp Race Starts: | 72 |
| Gp Championships: | 0 |
| Gp Race Wins: | 3 |
| Gp Podiums: | 12 |
| Gp Total Points: | 329 |
| Gp Poles: | 0 |
| Gp Fastest Laps: | 1 |
| Gp First Race: | 1972 50cc Dutch TT |
| Gp First Win: | 1972 50cc East German Grand Prix |
| Gp Last Win: | 1981 50cc Czechoslovakian Grand Prix |
| Gp Last Race: | 1987 80cc Portuguese Grand Prix |
Theo Timmer (born 6 March 1949) is a former Grand Prix motorcycle road racer from the Netherlands. He had his best season in 1981 when he won the Czechoslovakian Grand Prix and finished the season in second place, behind Ricardo Tormo. In 1972 and 1973 he was third in the championship. He built most of his own motorcycles. Jan Thiel and Martin Mijwaart were his teachers. The engine marks he used were Jamathi, Kreidler, Bultaco, Casal and Morbidelli. He was twice national champion.[2]