In Spanish function words and expressions can be classified as lexically stressed or unstressed. Unstressed function words are usually realized without word-level prominence. There is also a contrast between compounds with stress on all their components and compound with a single stress, on the last member. Both in the case of function words and in the case of compounds, the facts are idiosyncratic in some respects. In this paper, these facts are presented in some detail and an analysis along the lines of Liberman & Sproat’s (1992) proposal for English is made. In this analysis, unstressed elements join in a single prosodic word with following elements. Interestingly, Spanish differs from English in being right-dominant in both word- and phrase-level prosodic domains. Within each prosodic word only the stress of the last element is realized. I also discuss the nature of secondary stress in Spanish. It is tentatively proposed that two different secondary stress phenomena should be distinguished.