Slide guitar or bottleneck guitar is a particular method or technique for playing the guitar. The term slide is in reference to the sliding motion of the slide against the strings, while bottleneck refers to the original material of choice for such slides, which were the necks of glass bottles. Instead of altering the pitch of the strings in the normal manner (by pressing the string against frets), a slide is placed upon the string to vary its vibrating length, and pitch. This slide can then be moved along the string without lifting, creating continuous transitions in pitch.

Slide guitar is most often played (assuming a right-handed player and guitar):

• With the guitar in the normal position, using a slide called a bottleneck on one of the fingers of the left hand; this is known as bottleneck guitar.
• With the guitar held horizontally, with the belly uppermost and the bass strings toward the player, and using a slide called a steel held in the left hand; this is known as steel guitar.

Slides may be used on any guitar, but slides generally and steels in particular are often used on instruments specifically made to be played in this manner. These include:

• All steel guitars.
• Many (perhaps most) resonator guitars, particularly Dobros and their descendants.
• Lap slide guitars, particularly Weissenborns and their descendants.