Petrus Houttuyn (18 June 1648, Amsterdam – 10 January 1709, Leiden), often cited as Peter Hotton, was a Dutch botanist and medical professor of medicine and botany at Leiden University. As professor of botany, he was ex officio supervisor of the university's botanic garden and was given an official residence and an allowance for foreign correspondence and the exchange of seeds and plants. The genus Hottonia (family Primulaceae) is named in his honor.