Chief Simeon Olaosebikan Adebo (October 4, 1913 - September 30, 1994) was a Nigerian administrator, lawyer and diplomat who served as a United Nations Under-Secretary General.He was the former head of the civil service in Nigeria's old Western Region. As a chieftain of the Yoruba people residing in the historic mountain stronghold of Abeokuta, he held the title of the Okanlomo of Egbaland.