John J. Marshall suggested that this street was called after George Cadogan, 5th Earl of Cadogan Lord Lieutenant of Ireland (1895-1902). However, another possibility is that it belongs to a cluster of nearby streets named after Royal Navy admirals—Collingwood Avenue/Road and Curzon Street, Penrose Street—in which case it would commemorate Admiral George Cadogan, 3rd Earl Cadogan (1783-1864). The apparent tight themed cluster of four names speaks in favour of a name honouring Admiral Cadogan. On the other hand, it must be borne in mind that Cadogan Street was named more than three decades after his death, whereas the 5th Earl of Cadogan was Lord Lieutenant at this very time. The matter is, therefore, unresolved.
"Application of the owners the Martin Estates Company Ltd two new streets on their property off Donegall Road be named Kitchener Street and Soudan Street and three new streets off their property situate off Agincourt Avenue - Collingwood Avenue, Cadogan Street and Curzon Street". (Minutes, TIC, 12th October 1898).