Annie Armstrong (July 11, 1850 – December 20, 1938) was a lay Southern Baptist denominational leader instrumental in the founding of the Woman's Missionary Union.
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.
She worked with various Baltimore missionary organizations ministering to African Americans, Native Americans, Chinese Americans immigrants, and indigent women.
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.