Tiselius is a lunar impact crater that lies just to the east of Valier, on the Moon's far side.

Less than one crater diameter to the east of Tiselius is the smaller, elongated Stein, and to the north is the small, eroded Šafařík.

This is a roughly circular crater with a well-defined edge that has not been significantly degraded by impact erosion.

The small, cup-shaped satellite crater Tiselius E lies near the eastern outer edge.

[1] By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Tiselius.