Smoothing is the reduction or elimination in the roughness or unevenness of a surface or other thing.

Smoothing may refer to:

• Smoothing, a type of statistical technique for handling data
• Smoothing (phonetics)
• Image smoothing
• Relaxation (iterative method), iterative smoothing of solutions and errors in computational science
• The Smoothing problem in stochastic processes. See Smoothing problem (stochastic processes)