There is now plenty of evidence that the learning of multiword units can occur across the four strands of meaning-focused input, meaning-focused output, language-focused learning, and fluency development, although the largely unresearched strand with regard to multiword units is fluency development. There are now many useful well-researched lists of multiword units of various kinds. Multiword units tend to be acquired late and are one of the signs of high proficiency in a language. This chapter looks at various ways of classifying multiword units according to their form, meaning, and storage. It has many practical suggestions for supporting the learning of multiword units. These include learning through input, learning through output, consciousness raising, using flash cards, using mnemonic tricks such as alliteration and considering their origins, looking for patterns, using concordances, and fluency development.