Sigurd Engelstad (1914 – 2006) was a Norwegian genealogist and archivist.
Engelstad was born in Hadsel[1] as the son of jurist Sigurd Engelstad (1878–1916) and older brother of writer Carl Fredrik Engelstad. Through Carl Fredrik, Sigurd was the uncle of professor Fredrik Engelstad.[2]
Sigurd Engelstad published several genealogical works, and was a co-editor of the journal Norsk slektshistorisk tidsskrift from 1960 to 1975. From 1979 to 1983 he served as deputy archivist (førstearkivar) at the National Archival Services of Norway.[1]