Z3 may refer to any of the following:
1. Z3 was an electromechanical computer designed by Konrad Zuse, a German civil engineer, in 1935. He finished building the Z3 and introduced it to the public in 1941. It had 2,600 relays, 22-bit length words, and a clock speed of 5-10 Hz. The Z3 was the first functioning programmable computer and could be fully automated.