A barcode reader or barcode scanner is an optical scanner that can read printed barcodes, decode the data contained in the barcode on a computer. Like a flatbed scanner, it consists of a light source, a lens, and a light sensor for translating optical impulses into electrical signals.

Barcode readers capture and translate barcodes into numbers and/or letters for translation by computer. Barcode scanners can be connected to a computer through a serial port, keyboard port or interface device called a wedge.