Mickey Mouse has no established middle name in Disney’s official character name.
Disney identifies the character as Mickey Mouse, with “Mouse” serving as his surname or character name rather than part of a three-name personal identity. Stories and fan discussions sometimes invent middle names, but these are not part of the standard Disney characterization.
Mickey was created by Walt Disney and Ub Iwerks in 1928 and became one of the company’s central symbols. His name was originally proposed as Mortimer Mouse before Walt Disney’s wife, Lillian Disney, reportedly encouraged the name Mickey instead.
The absence of a middle name can be confused with fictional names used in particular cartoons, comics, or unofficial references. Disney has also given Mickey different occupations and settings over the decades, but his core name has remained stable. For a trivia answer, “None” is the canonical response rather than a speculative invented name.