Crispin Curtis Adeniyi-Jones (1876–1957) was a Nigerian medical doctor of Sierra Leonean heritage and the pioneer director of the Yaba asylum. He became one of Nigeria's foremost nationalist as a member and later president of the Nigerian National Democratic Party. He was also a longtime member of the legislative council of Nigeria and served in the council from 1923-1938. Apart from his political activities, he also teamed up with Winifred Tete-Ansa of the National Congress of British West Africa to formulate economic policies to alleviate some of the emerging economic problems in colonial West Africa.
Crispin Adeniyi-Jones was born in Freetown, Sierra Leone. He attended Sierra Leone Grammar School for secondary education and earned his university degrees at the University of Durham and the University of Dublin. He started work at Rotunda Hospital, Dublin, and later apprenticed under Sir Robert Boyce, a notable doctor from the Liverpool School of Tropical Medicine. He left Britain for Nigeria in 1904 and served in the government medical services in Lagos. However, a strategic policy to limit the advancement of African doctors within the medical services and the lack of funds in many departments curtailed some of his initial enthusiasm. Nevertheless, he was appointed the first director of the Yaba Asylum, one of the two asylums in Nigeria at the time. In 1914, he left government services and started a successful private clinic in Lagos.
On June 24, 1923, Adeniyi-Jones, Eric Moore and Egerton Shynglee joined Herbert Macaulay and Thomas Jackson to form the Nigerian National Democratic Party, also known as NNDP. The party capitalized on an initiative to allow elective representation into the legislative council and contested the three seats allowed Africans in Lagos. Adeniyi-Jones won a seat into the council in 1923 and served in the council for about fifteen years. As a member of the legislative council, he took on the mantle of defending the interest of indigenous Africans by engaging in debates with other members on major policy initiatives such as the practice of indirect rule and asking tons of questions about official colonial policy and its benefit to Africans. He sometimes offered strenuous opposition to official colonial policy affecting Nigerians in general. He brought the party's nationalistic initiatives to the public sphere and argued for the merits of traditional norms and customs especially those dealing with the selection of traditional chiefs.