Willem Pieterszoon Buytewech (1591/92 – September 23, 1624) was a Dutch Golden Age painter, draughtsman and etcher.

He is one of the early specialists in the merry company type of subject in Dutch genre painting.

After his marriage on November 10, 1613, with Aeltje van Amerongen, of a patrician family, he returned to Rotterdam.

Buytewech was primarily a graphic artist, mostly of landscapes and genre pieces, but occasionally also of biblical and allegorical themes.

Of his paintings only eight have survived to this date, all genre pieces, most depicting merry companies.