ABSTRACT  The Second Language Acquisition community has long held the homestay environment as the sine qua non of language study abroad (Davidson 1995; Brecht, Frank, Rivers, 1998a). Implicit in this view of the homestay environment is that a continuous immersion environment provides far greater authentic Target Language input than dormitory placements with non-native speakers of the Target Language. In turn, this increased quality and quantity of input should lead to greater language gains during study abroad than those achieved by students in dormitory placements. An evaluation of these hypotheses is now possible: the 1976–1996 American Council of Teachers of Russian Student Records Data Base, which contains proficiency and background data on over 2500 study-abroad participants, in both dormitory and homestay placements. Standard statistical techniques were used to compare gains made in Speaking, Listening, and Reading by dormitory and homestay participants. The following results obtain: homestay participants were slightly less likely to gain in speaking proficiency (mean rankdorm-stay= 547; mean rankhomesty= 431; χ=27.26 p<0005), were likely to gain less in Listening (mean rankdom-stay= 969; mean rankhomestay= 1132; χ=21.585; p<0005) and more likely to gain in Reading (mean rankdormstay= 969; mean rankhomestay= 1128; χ=20.713; p< 0005) than dormitory participants. These results stand counter to the intuition that greater auditory Target Language input would result in greater gains in Listening and possibly Speaking. Recent ethnographic research aimed at a description of the homestay environment (Frank 1996) and at learner behavior during study abroad (Brecht and Robinson 1995; Pellegrino 1997) provides an initial explanation for the “Homestay Effect.” Student preparation has a particularly strong influence on learning behaviors: experienced language learners may be more adept at managing the ceaseless flow of Target Language input than inexperienced learners. The results of the current investigation, along with recent work in Self-Directed Language Learning and Immersion, suggest that students in homestay environments may benefit from training in the management of linguistic input.