Horst Janssen Museum, Art museum in Oldenburg, Germany

The Horst-Janssen-Museum is an art museum in Oldenburg, Lower Saxony, dedicated to the draftsman, etcher, lithographer, wood engraver, poster artist and illustrator Horst Janssen. It opened in 2000 with 1,800 sheets from the collection of Carin and Carl Vogel, acquired in 1995 by the Oldenburg entrepreneur Claus Hüppe for 1.5 million DM. The building, designed by Peter Reinig, Meike Dreyer and Carl Deters, has three exhibition levels: level 1 holds the permanent exhibition, levels 2 and 3 host three to four temporary exhibitions a year. The museum shares its entrance with the Stadtmuseum Oldenburg.

In 1995 the Oldenburg entrepreneur Claus Hüppe bought the Janssen collection of the Hamburg couple Carin and Carl Vogel for 1.5 million DM, providing the basis for the building. The museum, designed by Peter Reinig, Meike Dreyer and Carl Deters, opened in 2000 with 1,800 sheets. In November 2016 the Stefan Blessin collection of 315 watercolours, prints and drawings was sold to the museum for 1.5 million euros, handed over in April 2017.

The museum's library holds 25,000 art volumes, including nearly all of Janssen's own publications. In a separate reading room, visitors can request to see drawings and prints from the collection. The Claus Hüppe Foundation regularly awards the Horst Janssen Print Prize, accompanied by an exhibition of the winner's work.

The museum shares its entrance with the Stadtmuseum Oldenburg, so one visit can cover both. The permanent exhibition is on level 1, while levels 2 and 3 host three to four temporary exhibitions a year. Original works are rotated three times a year, so repeat visitors see different pieces.

The 1,800 sheets that opened the museum in 2000 came from Carin and Carl Vogel's Hamburg collection, bought in 1995 for 1.5 million DM by Oldenburg entrepreneur Claus Hüppe. In 2016 the museum acquired 315 watercolours, prints and drawings from Stefan Blessin for 1.5 million euros, giving it its own holdings alongside the permanent loans.