[3] The specific name millsoni refers to Mr. Alvan Millson, assistant colonial secretary in Lagos and the collector the two female syntypes.

[2][7] Leptopelis millsoni was described by the Belgian-British zoologist George Albert Boulenger in 1895 based on the syntypes from the Niger Delta.

However, as these comparisons did not involve materials from the type locality of L. millsoni (the Niger delta), the question whether this name applies to the West African species (L. macrotis as currently defined) is not resolved.

If this were the case, name Leptopelis guineensis would be available for the Central African species (L. millsoni as currently defined).

It is typically found near large, slow-flowing watercourses;[1] the males call from branches close to such streams.