A barbell is a piece of equipment used in weight training, weightlifting and powerlifting. It consists of a steel bar that is about 2 metres long. The centre portion is one inch (2.54 cm) in diameter, and is engraved with a crosshatch pattern (knurling) to help lifters get a good grip. Cast iron disc weights (plates) are slid onto the outer portions of the barbell to obtain the desired total weight. These weights are often secured with collars to prevent them from sliding off during the exercise (which can result in injuries).

There are two types of plates, and therefore two types of barbells:

• Olympic plates have a central hole that is two inches (5.08 cm) wide. The outer portions of Olympic barbells are also two inches wide.
• Standard plates have a central hole that is one inch (2.54 cm) wide. Standard barbells are one inch wide all the way along.

Exercises that can be performed with a barbell include:

• Bench press
• Squat
• Deadlift
• Bicep curl

The EZ curl bar is a variant of the barbell that is often used for the bicep curl exercise. Its zigzag grips allow the user's wrists to take a more natural orientation. This reduces the risk of repetitive stress injury in this exercise.

"Barbell" is also the name of a very common design of body piercing jewelry.