| Emil Knoevenagel | |
| Birth Date: | 18 June 1865 |
| Birth Place: | Hannover, Kingdom of Hanover |
| Nationality: | German |
| Death Place: | Berlin, Germany |
| Doctoral Advisor: | Viktor Meyer |
| Known For: | Knoevenagel condensation |
Heinrich Emil Albert Knoevenagel (pronounced as /de/; 18 June 1865 - 11 August 1921) was the German chemist who established the Knoevenagel condensation reaction. The Knoevenagel condensation reaction of benzaldehydes with nitroalkanes is a classic general method for the preparation of nitroalkenes, which are very valuable synthetic intermediates.