Classifier phrases are phrases with a classifier or measure element and a classifier interpretation; measure phrases are phrases with a classifier or measure element and a measure interpretation. Rothstein’s generalization says that classifier phrases pattern semantically with count nouns, while measure phrases pattern semantically with mass nouns. The present chapter compares closely related proposals by Rothstein and Landman about the structure and interpretation of these phrases. These theories assume the same interpretation for classifier and measure phrases. They differ in the syntax they assume for Dutch and English measure phrases: left branching structures for Rothstein, right branching structures for Landman. Crucially, in Landman’s (more traditional) syntax, but not in Rothstein’s, the measure is the syntactic head of the measure phrase. Section 9.5 makes a detailed case for Landman’s syntax for measure phrases in Dutch and English, and in particular for the head status of measures. Section 9.6 makes Landman’s proposal part of a more general proposal which can accommodate a version of Rothstein’s left branching syntax for Mandarin and Hebrew, and other proposals for classifier languages that differ from Mandarin, like Japanese.