Johannes Posthumus
| Johannes Posthumus | |
|---|---|
| — Gymnast — | |
| Country represented |
 Netherlands |
| Born |
September 24, 1887 Gouda |
| Died |
December 12, 1978 (aged 91) Utrecht |
| Discipline | Men's artistic gymnastics |
Johannes Jacobus Posthumus (September 24, 1887, in Gouda – December 12, 1978, in Utrecht) was a Dutch gymnast who competed in the 1908 Summer Olympics.
He was part of the Dutch gymnastics team, which finished seventh in the team event. In the individual all-around competition he finished 66th.