This study examines whether pronunciation instruction can improve listening comprehension in a second language. At the most basic level, listening comprehension involves the perception of individual sounds and sound contrasts, a process that is known to be related to production, or pronunciation, within the L2 phonological system. As improving listening comprehension has been cited as a reason to teach pronunciation in the L2 classroom (Arteaga, 2000; Brown, 1992; Gilbert, 1995), this study tests whether the positive relationship between pronunciation instruction and perception can be born out empirically using the case of /s/ aspiration in Spanish with native English speaking students.