Freiburg Charterhouse (Kartause Freiburg) is a former Carthusian monastery, or charterhouse, in Freiburg im Breisgau, Baden-Württemberg, Germany.
Freiburg Charterhouse was founded in 1345 or 1346 by Johannes Schnewlin (Snewelin, Snewlin), knight, Bürgermeister of Freiburg. It was dedicated to Saint John the Baptist, in honour of the Grande Chartreuse near Grenoble, and was known as Sankt Johannisberg or St. Johannes des Täufers Berg ("St John's Mount" or the "Mount of St. John the Baptist"). It was to begin with a very modest establishment of only two monks' cells, increased on the death of the founder in 1347 to five. The original endowment consisted of a piece of land on the Mussbach below Sankt Ottilien; later endowments made it possible to increase the number of cells to twelve.
In the early 16th century, the premises were extended by the addition of the refectory and the church, which was constructed in the Late Gothic style with ribbed vaulting and flying buttresses. It featured magnificent stained glass windows to designs by the Swabian painter Hans Baldung Grien.
At its height the charterhouse maintained close contact with the University of Freiburg. From 1502 to 1525 the prior was Gregor Reisch, a significant representative of late Scholasticism and a professor at the university. The monastery supported impoverished students and in its turn received donations and novices from the circles round the university.
The monastery gradually built up a significant library, particularly through its contact with the university, mainly through the gifts of new entrants to the monastery, and also through legacies from university staff and local clergy. For example, in 1537 the monastery inherited the library (consisting of c. 390 books) and the estate of Otmar Nachtgall.