Olive Tiller set up an American Baptist presence in Washington DC under the Division of Christian Social Concern of the ABC in 1965. She participated in the March 9, 1965 march to Selma, Alabama, representing the ABC. She spent eight weeks visiting church women in Malawi, Tanzania, Kenya, Ghana, Sierra Leone and South Africa in 1966, as one of eleven laywomen to open communication to women in Africa, under the auspices of US Church Women United. She also served on the executive committee of US Church Women United with Coretta Scott King. Tiller worked at Gallaudet College for the deaf, attended Clown School and joined the National Council of Churches staff in 1981. She served as ecumenical office in the Office of the General Secretary for the ABC, president of the Baptist Peace Fellowship and spent much of the 1990s in volunteer service, planting trees in Malawi, building houses in Hungary and Tanzania, and teaching English in Italy. While working with Habitat for Humanity in Tanzania, she helped with funding for the Ulaya Secondary School, and the girls’ dormitory was named in her honor, Olive Tiller Girls’ Dormitory.