|Abstract:||This paper documents three different sites in which the grammar of Standard Italian offers the choice between open vs. closed mid vowels in stressed position: stress shifts on the base due to affixation and various truncations (hypocoristics and acronyms), statistical biases in the lexicon, and loanword adaptations. We find that in all three, open vowels are chosen over closed. This phenomenon is analyzed as optimizing the relation between vowel sonority and stress—not by shifting stress but by altering vowel height—and provides a stressed syllable counterpart to the better known raising of unstressed mid vowels to closed. An OT grammar employing stringency constraints (de Lacy 2004, 2006) is proposed. Parallel phenomena in Brazilian Portuguese and Catalan are briefly noted. The paper then reports a small experiment to support some of the phonetic assumptions underlying the analysis: that sonority (duration) aligns with vowel height and that the choice of open over closed mid vowels is a matter of markedness rather than faithfulness. The paper closes with a discussion of Slovene where stressed mid vowels in English loanwords are adapted as closed rather than open (Jurgec 2009). Phonetic evidence indicates that duration does not align with vowel height in contemporary Standard Slovene. The paper suggests that closed vowels are chosen for reasons of phonetic dispersion.