The resophonic guitar, often known as the dobro, is a stringed instrument that was developed in the 1920s and 1930s as an attempt to create a louder guitar. In bluegrass music the resophonic guitar is played with a metal tone bar, and is therefore technically considered to bea form of acoustic steel guitar.

The resophonic guitar was popularised in bluegrass by Josh Graves, resophonic guitarist of the Foggy Mountain Boys. Today the resophonic guitar is often associated with modern bluegrass, and is played by progressive musicians such as Jerry Douglas, Rob Ickes, and Andy Hall.