There are many reasons to believe that oral participation in the target language (TL) is beneficial for classroom language learners. In addition to the prominence current second language acquisition (SLA) theory gives to processes that assume learner production of the TL (e.g. negotiation of meaning), teachers often view oral participation as a measure of learner involvement. Thus, it is often assumed that learners who participate often are likely to make greater proficiency gains. This correlational study examined this assumption by investigating the relationship between learners' oral participation in classes for English as a foreign language (EFL) at a Japanese university and their gains in TL proficiency. Results indicated that while the quality of learners' participation (accuracy, complexity, and fluency) was positively related to gains in TL ability, quantity of participation was not. While not indicative of a cause-effect relationship, the results suggest that teachers might wish to consider encouraging quality of participation as well as quantity. (Contains 5 tables.)