What clef does the marimba play in?

Answer 1

Usually a marimba, played with 2 mallets it is written in treble cleff.

When playing with four mallets, usually the part for the right hand is written in treble cleff, and the part for the left hand is written in bass clef

Answer 2

The marimba is written for both treble and bass clefs. The range of the standard 5-octave marimba is from the C right below the staff in the bass clef to the 2nd C above the treble staff.