Ælsinus (10th century), was an Anglo-Saxon miniaturist, and a monk of New Minster, or Hyde Abbey, Winchester. In a Miscellany among the Cotton MSS. in the British Library there is an "Office of the Holy Cross", written by Ælsinus for , afterwards abbot of Hyde. It is ornamented with miniatures of the Crucifixion and the Blessed Trinity. The miniatures are in outline of a greenish tint. Prefixed to the "Office" is a calendar commencing in 978, which is probably the date of the "Office".