Eubranchus horii is a species of sea slug or nudibranch, a marine gastropod mollusc in the family Eubranchidae.

[2] This species was described from Hayama, Sagami Bay, Japan.

Additional specimens included in the original description were from Tannowa, Osaka Bay; from among a hydroid colony on Ecklonia leaves at Mukaishima, Seto Inland Sea and from Abugashima, Toyama Bay.

[1] It has been photographed at Kurosaki, Toyama Bay.

[3]