Hendrik Detmers (20 March 1761 – 8 September 1825) was a Dutch military officer who played an important part in the Battle of Waterloo as a colonel, commanding a brigade.

[1] Apparently an ardent Orangist he joined the "Osnabrück Assembly,"[3] a group of former soldiers around Prince Frederick of Orange-Nassau who wanted to stage a raid into the Batavian Republic in the summer of 1795.

When the French Imperial Guard undertook its famous assault on the Allied right wing toward the end of the day, and the British line was hard pressed, the Dutch Third Division was ordered forward at the initiative of general Chassé.

The 4th Grenadiers of the French Middle Guard were severely attacked by the battery of horse-artillery of the Dutch division, under command of captain Krahmer de Bichin, but they kept advancing.

The British line (1/3rd Foot) poured fire onto the Guard, and general Chassé ordered Detmers to charge the French column with his brigade.

The Dutch troops advanced in a state of high excitement, cheering wildly and lifting their shakos on their bayonets, according to a British eye-witness (captain Edward Macready, 2/30th regiment of Foot).

[9] Kyle van Beurden in his dissertation remarks that Wellington in his report to the Dutch king William made clear that he had actually intended to compliment major-general Alexander d'Aubremé, the commander of the 2nd brigade of the 3rd Netherlands division.