The term Unfederated Malay States was the collective name given to five British protected states in the Malay peninsula in the first half of the twentieth century. These states were Johor, Kedah, Kelantan, Perlis, and Terengganu. In contrast with the four neighbouring Federated Malay States of Selangor, Perak, Pahang, and Negri Sembilan, the five Unfederated Malay States lacked common institutions, and did not form a single state in international law. In fact, there is no such unit as Unfederated Malay States in history; they are in fact standalone British protectorates. Such naming was added by later historians to differentiate from the Federated Malay States.
Johor accepted a treaty of protection with the United Kingdom in 1885, and eventually succumbed to British pressure to accept a resident "Advisor" in 1904. Unlike the other Malay states under British protection, however, Johor remained outside of the Federated Malay States (formed in 1895).
The chief officer of the Britishcolonial administration was the "Advisor". In contrast with the Federated Malay States, the Unfederated Malay States enjoyed greater autonomy. The de facto official language of the Unfederated Malay States was Malay (written with the Jawi script).