Sir John Frederick Bridge CVO (5 December 1844 – 18 March 1924) was an English organist, composer, teacher and writer.

From a musical family, Bridge became a church organist before he was 20, and he achieved his ambition to become a cathedral organist by the age of 24, at Manchester Cathedral. After six years there, he was invited to become organist at Westminster Abbey, where he remained for the rest of his career. He instituted several changes to modernise and improve the music-making at the Abbey and organised the music for several state occasions, including two coronations.

As a teacher and lecturer, Bridge held posts at the Royal College of Music, Gresham College and the University of London. His students included the composers Arthur Benjamin and Noel Gay, the organists Edward Bairstow and Herbert Brewer, the conductor Landon Ronald and the early music pioneer Arnold Dolmetsch. His public lectures at Gresham College attracted large audiences, and they covered a wide range of subjects and musical periods.

For 25 years, Bridge was conductor of the Royal Choral Society, with whom he performed many new works, including some of his own compositions and works by the British composers Elgar, Vaughan Williams and Parry.

Bridge was born in Oldbury, then in Worcestershire, in central England, the eldest son of John Bridge and his wife, Rebecca née Cox. In 1850, his father was appointed a vicar-choral of Rochester Cathedral. Young Bridge was admitted to the cathedral choir as a "practising boy" (that is, a probationer). The choirboys were educated by another of the vicars-choral. The régime was severe in discipline and rudimentary in curriculum, but among the alumni of the choir school of this period were future organists of four English cathedrals and of Westminster Abbey. They included Bridge's younger brother Joseph, who eventually became organist of Chester Cathedral.

Bridge first participated in a great national commemoration in 1852, when, aged eight, he was allowed to help toll the cathedral bell to mark the death of the Duke of Wellington. When Bridge was nine, he and his father were members of the choir assembled by Michael Costa for the opening of the Crystal Palace in June 1854. At the age of 14 Bridge left the cathedral choir and was apprenticed to John Hopkins, organist of Rochester Cathedral. While still studying under Hopkins, Bridge was appointed organist of the village church of Shorne in 1851, and the following year moved to Strood Parish Church. From 1863 to 1867 he studied composition with John Goss, professor of harmony at the Royal Academy of Music. Bridge said in 1897, "Very happy and improving lessons they were and it is impossible for me to over-estimate the value of the instruction given by that dear, simple-minded musician."

In 1865 Bridge was appointed organist of Holy Trinity Church, Windsor. There he was encouraged and influenced by George Job Elvey, organist of St. George's Chapel, Windsor, and made many friends including John Stainer and the young Hubert Parry. During his time at Windsor, Bridge passed the examination for the Fellowship of the Royal College of Organists, in 1867, and took his Bachelor of Music degree at the University of Oxford.

After four years at Windsor, Bridge achieved his ambition to become a cathedral organist, successfully competing for the post at Manchester Cathedral. He spent six years there from 1869, with his brother Joseph as his assistant. While at Manchester, he took his Doctor of Music degree at Oxford in 1874, and was professor of harmony at Owens College from 1872.