E9 tuning is a common tuning for steel guitar necks of more than six strings. It is the most common tuning for the neck located furthest from the player on a two-neck console steel guitar or pedal steel guitar while a C6 neck is the one closer to the player. The E9 is a popular tuning for single neck instruments of eight or more strings. This tuning has evolved in the last half of the twentieth century with input from prominent performers including Jimmy Day, Ralph Mooney and Buddy Emmons to support optimal chord and scale patterns across a single fret on the 10-string pedal steel guitar.

Corresponding tunings for a six string lap steel guitar are the E6 tuning E–G♯–B–C♯–E–G♯, or E7 tuning B–D–E–G♯–B–E.

A popular E9 tuning for eight string console steel guitar is the Western swing tuning E–G♯–B–D–F♯–G♯–B–E, low to high and near to far.

The standard Nashville E9 tuning also called the E9 Chromatic Tuning^: 7 for ten string pedal steel guitar is B–D–E–F♯–G♯–B–E–G♯–D♯–F♯.