In this talk, I present an overview of a lesser-known method, pupillometry, a natural, real-time measure of pupil dilation. Traditionally used to study cognitive response to memory, cognitive and attentional load, and emotional valence, pupillometry has also been used as a measure of effort expended in language comprehension. Increased pupil size has been observed for syntactically complex sentences (Engelhardt et al., 2010), violations of expected meter (Scheepers et al., 2013), and inadequate or misleading pitch accent (Zellin et al., 2011). I present a series of ongoing studies on classic attachment ambiguities in English, suggesting that the pupil responds to mismatches between prosodic and syntactic grouping. Preliminary analyses suggest that penalties for prosodic mismatch are also modulated by violation of additional structural or pragmatic expectations. I discuss implications for theories of prosody-syntax alignment in real-time sentence parsing, along with a comparison of the practical, methodological, and interpretive tradeoffs associated with this method.