Early life 
Annie Walker Armstrong was born in Baltimore, Maryland to tobacconist John Dunn Armstrong and his wife Mary Elizabeth Armstrong. She also had a brother named James. She came from a long line of prominent Baptists including her great-great-grandfather Henry Satre who help establish the first Baptist church in Maryland. At the age of 20, she accepted Christ as her Savior under the preaching of Dr. Richard Fuller at Seventh Baptist Church (now Seventh Metro Church). It was there that she had a "born again" experience and was equipped to be a missionary. Later, she was among 100 Seventh Baptist Church members who established Eutaw Place Church (now Woodbrook Baptist Church). The church was pastored by Richard Fuller, the third president of the Southern Baptist Convention, who was heavily involved in missionary activities.
Woman's Missionary Union 
In 1888, Armstrong led the creation of the Woman's Missionary Union, helping draft the constitution and serving as its first correspondent secretary (a position that functioned as executive director).
In her role as the head of the organization, Annie Armstrong facilitated communication between denominational leaders, local congregations and missionaries on the field. She was an extensive letter writer, handwriting 18,000 letters in one year alone.
During her tenure as head of the WMU, Armstrong refused a salary and traveled at her own expense on behalf of the WMU.
Controversies and Conflicts 
Beginning in 1895, Armstrong became involved in a series of controversies and conflicts with other WMU leaders. When Fannie E.S. Heck, the president of the Union, opposed her on an issue regarding how to integrate Sunday Schools in missionary work, Armstrong declared, "either she must resign or I shall!".
On the heels of the internal conflict within the WMU, Armstrong became embroiled in a denominational conflict over the establishment of a missionary training school at Southern Baptist Theological Seminary in Louisville, Kentucky. Armstrong opposed the establishment of a school on several grounds. She argued that the WMU's funds should be directed exclusively towards missionary work on the field. In 1906, Armstrong became outspoken in her opposition to the training school when it began accepting female students, holding that seminaries should educate exclusively men and a fear that it was laying groundwork for the ordination of women.
In that same year, an editorial critical of her opposition to the school appeared in a denominational newspaper. Taking the editorial and other criticism of her opposition as a personal attack, she resigned from the WMU, vowing to never again serve the denomination.
Though she kept her promise, she remained active in her local congregation and missions in the city of Baltimore.
However, towards the end of her life, she allowed an Easter collection of funds for home missions to be collected in her name, and made a conciliatory address to the WMU where she expressed the hope that the WMU would become "stronger with each successive year".
She died on December 20, 1938 in Baltimore, the year the WMU celebrated its fiftieth anniversary.
- "Biography of Annie Armstrong". Southern Baptist Historical Library and Archives. Retrieved 6 April 2011.
- Baker, Sharon (March 2006). "Following in the footsteps of Annie Armstrong in Baltimore" (PDF). BaptistLife (Columbia, Maryland: Baptist Convention of Maryland and Delaware). pp. 1, 6–7. ISSN 331-640). Archived from the original on 2008-05-29. Retrieved 2008-04-19.
- Don Whitney (September 1992). "Richard Fuller, Part 2: His Preaching". The Founders Journal. Founders Ministries. Archived from the original on 5 May 2008. Retrieved 2008-04-23.
- "Woodbrook Historical Highlights". Woodbrook Baptist Church. (undated). Retrieved on April 18, 2008.
- "Annie Armstrong". Woman's Missionary Union's official website. Archived from the original on 16 May 2008. Retrieved 2008-04-19.[dead link]
- "Who is Annie Armstrong?". North American Mission Board's official website. Archived from the original on 2008-04-02. Retrieved 2008-04-19.
- Armstrong, Annie (2006). Keith Harper, ed. Rescuing the Perishing: The Correspondence of Annie Armstrong. Macon, Georgia: Mercer UP. pp. 1–8. ISBN 0-86554-843-9.