William J. Dreyer, Ph.D. (1928 – April 23, 2004) was a molecular immunologist and California Institute of Technology (Caltech) professor of biology from 1963 to 2004. He completed his Ph.D. in biochemistry at the University of Washington in 1956. Dreyer then went to work at the National Institutes of Health as a National Polio Foundation postdoctoral and as a research scientist studying the genetic code. While at NIH, he invented machinery for automating biochemical analyses. In 1963, he was appointed professor in biology division of Caltech. He collaborated with J. Claude Bennett researching the genetic coding for protein structure, gene splicing and monoclonal antibodies.