Social Reformer. As founder of the Woman's Missionary Union (WMU), she was a leader in Southern Baptist evangelization efforts for many years. Raised in a prominent Baltimore, Maryland family, she was baptized in the Seventh Baptist Church of Baltimore at 19 and soon became a founding member of Eutaw Place Baptist Church, where she was to be active for a number of years. In 1880, she heard a lecture on the plight of the Native Americans living in Oklahoma; she and other ladies organized relief efforts, which led, in 1882, to her becoming the founding president of the Women's Baptist Home Mission Society of Maryland. As a delegate to the Southern Baptist Convention at Richmond, Virginia, in 1888, she was the driving force for starting the WMU, of which she was to be corresponding secretary (executive director) until 1906. That same year, she was responsible for collecting $2,883.49 to send to missionary Lottie Moon in China, the first "Lottie Moon Christmas Offering". Taking as her motto "Go Forward!", she made the WMU an auxillary of the Southern Baptist Convention, with the authority to raise money and select its own missionaries. She was instrumental in reaching out to African-American, Chinese immigrant, and Indian congregations, and commissioned the first two Black female missionaries. Always working without salary, and paying her own expenses, she kept busy with her home church, the WMU, and with writing for Southern Baptist publications. She resigned from her position and from the organization in 1906 due to disagreement over a move to pay the corresponding secretary, and to make the WMU training school a part of the Southern Baptist Seminary in Louisville, Kentucky. She remained active in local Baltimore missions to the end of her life. Today she is enshrined in the Maryland Women's Hall of Fame, the Woman's Missionary Union continues its work, and the "Annie Armstrong Easter Offering for North American Missions" is collected (as is the Lottie Moon Offering) in Southern Baptist Churches.