The disclosure discloses an array substrate, a display panel, and a display device, and the array substrate includes: a plurality of data lines arranged in a display area, and a demultiplexer assembly, a test switch assembly, and a plurality of data signal fanout wires, arranged respectively in a non-display area, where each of the signal output terminals of the demultiplexer assembly is electrically connected with one of the plurality of data lines, each of the signal input terminals of the demultiplexer assembly is electrically connected respectively with one of the plurality of data signal fanout wires, and one of the output terminals of the test switch assembly; and the test switch assembly is arranged on the side of the demultiplexer assembly away from the display area.