ZF 4-speed automatic Karosa B 931 is an urban bus produced from 1996 to 2002 by bus manufacturer Karosa from the Czech Republic, in the years of 1996 to 2002.

The body is semi-self-supporting with frame and engine with automatic gearbox in the rear part.

First ten serial buses were made at the end of 1995 for Prague transport company.

Since 1999 were buses produced only in modernised version B931E, which has new solid front axle Škoda-LIAZ, floor lowered in front part by 10 centimeters, ABS and ASR.

Currently, number of Karosa B931 buses is decreasing, due to supply of new low-floor buses, for example by SOR NB 12 made in Czech Republic.