Frank den Os (b. 1965, Dordrecht, NL) is a visual artist based in Crozon sur Vauvre, France.

His work centres on A Measure of Days, an ongoing daily collage practice begun in February 2024. One collage is made each day. Over time, the works accumulate into a larger field in which relationships emerge through repetition and variation. This process extends into painting, where elements reappear at a different scale in a more fluid and spatial form.

Den Os has exhibited internationally, with recent exhibitions in France, South Korea, Latvia, the UK and the United States. His work is held in private collections across Europe, the UK and the United States.

Before focusing on visual art, he worked as a playwright for national and international theatre productions.