| Honorific Prefix: | Lieutenant general |
| Fons Aler | |
| Office: | Chairman of the United Defence Staff of the Armed Forces of the Netherlands |
| Term Start: | 10 January 1953 |
| Term End: | 1 October 1953 |
| Predecessor: | Vice admiral Edzard Jacob van Holthe |
| Successor: | General Ben Hasselman |
| Birth Name: | Izaäk Alphonse Aler |
| Birth Date: | 3 May 1896 |
| Birth Place: | Amsterdam, Netherlands |
| Death Place: | Rolde, Netherlands |
| Allegiance: |  Netherlands |
| Serviceyears: | 1917-1953 |
| Rank: | Lieutenant general |
| Battles: | World War II |
Lieutenant general Fons Aler (3 May 1896 – 21 December 1981) was a Dutch military officer who served as Chairman of the United Defence Staff of the Armed Forces of the Netherlands between January 1953 and October 1953. In 1997 a Fokker 50 of the Royal Netherlands Air Force was named after Aler.[1]