Frances Jane van Alstyne (née Crosby; March 24, 1820 – February 12, 1915), more commonly known as Fanny J. Crosby, was an American mission worker, poet, lyricist, and composer. She was a prolific hymnist, writing more than 8,000 hymns and gospel songs, with more than 100 million copies printed. She is also known for her teaching and her rescue mission work. By the end of the 19th century, she was a household name.

Crosby was known as the "Queen of Gospel Song Writers" and as the "Mother of modern congregational singing in America", with most American hymnals containing her work. Her gospel songs were "paradigmatic of all revival music", and Ira Sankey attributed the success of the Moody and Sankey evangelical campaigns largely to Crosby's hymns. Some of Crosby's best-known songs include "Pass Me Not, O Gentle Saviour", "Blessed Assurance", "Jesus Is Tenderly Calling You Home", "Praise Him, Praise Him", "Rescue the Perishing", and "To God Be the Glory". Some publishers were hesitant to have so many hymns by one person in their hymnals, so Crosby used nearly 200 different pseudonyms during her career.

Crosby also wrote more than 1,000 secular poems and had four books of poetry published, as well as two best-selling autobiographies. Additionally, she co-wrote popular secular songs, as well as political and patriotic songs and at least five cantatas on biblical and patriotic themes, including The Flower Queen, the first secular cantata by an American composer. She was committed to Christian rescue missions and was known for her public speaking.