Poecilobothrus majesticus is an extinct species of fly in the family Dolichopodidae that was endemic to Great Britain.

The species is known from a single male specimen collected near the Essex coast in Walton-on-the-Naze in 1907, and it was formally described by E. C. M. d'Assis-Fonseca in 1976.

Many years later, D'Assis-Fonseca rediscovered this specimen deposited in the Oxford University Museum of Natural History, in the Verrall-Collin collection of the Hope Department.

In 1976, D'Assis-Fonseca published a formal description of a new species based on the specimen, named Poecilobothrus majesticus.

He reported that it had a label identifying it as Poecilobothrus bigoti, but stated that it didn't fit Josef Mik's original description of that species.