This article covers the use of acoustics as a molecular probe of polymer structure and describes various acoustic applications of polymers. Sound speed and sound absorption measurements in polymers are useful both as a probe of the molecular structure of polymers and as a source of engineering design properties. Enough theory and experimental details are given to make the presentation understandable, but the emphasis is on the experimental results for polymers. Most of the presentation is for small‐amplitude waves in solid polymers. References to some specialized topics are given.