| Josef Knottenbelt | |
| Country: | Netherlands |
| Fullname: | Joannes Henricus Knottenbelt |
| Native Name: | Joop Knottenbelt |
| Birth Date: | 25 October 1910 |
| Birth Place: | Lhokseumawe, Sumatra[1] |
| Death Place: | Altea, Spain[2] |
| Wimbledonresult: | 2R (1931) |
| Wimbledondoublesresult: | 2R (1931) |
| Wimbledonmixedresult: | 4R (1932) |
Joannes Henricus "Joop" Knottenbelt internationally known as Josef Knottenbelt (1910 – 1998) was a Dutch tennis player. He was a member of the Netherlands Davis Cup team with among others Henk Timmer.
In 1927 he won the Dutch youth (under 18) championships.[3] In 1931, Knottenbelt reached the second round of the men's singles at Wimbledon, losing to Eberhard Nourney of Germany, 8–10 6–2, 0–6 9–11.[4] In the 1932 Wimbledon mixed doubles, he and Madzy Rollin Couquerque lost in the fourth round to Ellsworth Vines and Helen Wills-Moody.[5] [6]
In the quarterfinals of the 1934 Davis Cup, he lost to Swedes Curt Östberg (1–6, 1–6, 4–6) and Kalle Schröder (1–6, 5–7, 0–6) although the Netherlands won the round.[7]
Knottenbelt was born in the Dutch East Indies but grew up in Bussum. His younger brother Anthony Knottenbelt was also a promising tennis player, but died at the age of 19 after an accident.[8] In September 1937 Knottenbelt left again for the Dutch East Indies.[9]