Willem van Ingen, or Guilhelmo Den Eersten (1651–1708), was a Dutch Golden Age painter active in Italy.

According to Houbraken, he learned to paint in Utrecht and attracted the attention of Johannes van Neercassel, who took him along on a trip to Rome.

In Rome, he registered in the Bentvueghels as Guilhelmo den Eersten.

[1] Houbraken goes on to mention that he worked for a year in Rome under Karel Marat, painting in many churches, and then traveled to Venice where he worked for Valentin Lefebvre painting on copper after Paolo Veronese.

[2] He is known as the teacher of Albert van Spiers (1665–1718),[3] who was the teacher of Jacob de Wit, decoration painters in Amsterdam.