This article argues that English noun-plus-noun constructions (‘NNs’) originate both in the lexicon and in the syntax. It distinguishes between complement–head and attribute–head NNs, as well as between fore-stressed and end-stressed NNs. It argues that complement-head NNs are fore-stressed and originate in the lexicon while attribute–head NNs typically have end-stress and syntactic provenance. The latter are, however, potentially subject to diachronic lexicalization, which may moreover involve the adoption of fore-stress. Hence, lexical NNs may be fore-stressed or end-stressed while phrasal NNs must be end-stressed. Although further potential sources of irregularity are identified, it is demonstrated that the model's predictive power is fairly robust and that, where it fails to predict firm stress patterns, it predicts their variability.