ABSTRACT The aim of this paper was to examine the extent of non-verbalizable knowledge L1 Brazilian Portuguese (BP) learners of English possess about the segmental inventory of the L2. The study had two aims: i) to determine to what extent L1 BP EFL learners are aware of contrastive and non-contrastive L2 segments, ii) to determine which type of segments present the lowest level of awareness. To the date, little research has been carried out about the non-verbalizable aspect of L2 phonological awareness, most studies having relied on participants’ verbalization of the acquired knowledge (e.g., KENNEDY & TROFIMOVICH, 2010; WREMBEL, 2011). Whereas language learners are frequently taught grammar explicitly, pronunciation of the L2 is rarely addressed in the foreign language classroom. Moreover, phonology is in nature less susceptible to conscious processing than other aspects of L2 learning, making the noticing, and especially the explicit explanation, of phonological aspects difficult. Nevertheless, high L2 phonological awareness is beneficial for L2 pronunciation (KIVISTÖ-DE SOUZA, 2015), making its examination a priority in the foreign language classroom context. The participants of the study were 71 advanced EFL learners and 18 native speakers of American English. Participants performed a perception test which presented English segments spoken by native and non-native speakers. The ability to identify pronunciation deviations in the non-native speaker trials was taken as a measure for phonological awareness. The results showed that the L1 BP participants manifested a significantly lower sensitivity to English segmental phonology than the native English speakers (F[1, 87] = 40.56, p <.001, η2=.31). Pronunciation deviations involving consonants were identified to the greatest extent (52%), whereas the trials involving short-lag VOTs were identified the poorest (33%). The results reveal a need for explicit pronunciation instruction and the employment of consciousness-raising activities in the Brazilian EFL classroom.