Electro Scientific Industries, Inc. (ESI) is an American high technology company headquartered in the Portland, Oregon, metropolitan area, specifically in Beaverton, Oregon, since 2021, but from 1963–2021 it was based in the unincorporated Cedar Mill area just north of Beaverton. ESI is a developer and supplier of photonic and laser systems for microelectronics manufacturers. Founded in 1944, it is the oldest high-tech company in Oregon. Along with Tektronix, and later Intel, it has spawned numerous technology-based companies in the Portland area, an area known as the Silicon Forest. From 1983 to 2019, shares in the company were publicly traded on NASDAQ, under the ticker symbol ESIO.