Osias Beert (Antwerp, c. 1580 – 1624) was a Flemish Baroque painter who specialized in flower and "breakfast"-type still lifes. He joined the city's Guild of St. Luke in 1608, and trained Frans van der Borch, Frans IJkens, Paulus Pontius and Jan Willemssen. Beerts's floral paintings, often showing a vase of flowers in a shallow niche, are similar to the works of Ambrosius Bosschaert. His breakfast pieces, frequently known by their Dutch name ontbijtjes ("little breakfasts"), are seen from a high angle with forced perspective, as was common in both Flemish and Dutch still life painting in the early years of the seventeenth century. He might have also collaborated with Peter Paul Rubens.
- Mulders, Christine van. "Beert [Beet, Beirt, Bert], Osias [Osyas], I," Grove Art Online. Oxford University Press, [8 November 2007].
- Vlieghe, Hans (1998). Flemish Art and Architecture, 1585-1700. Pelican history of art. New Haven: Yale University Press. ISBN 0-300-07038-1
- Osias Beert at PubHist