This study examined Australian English (AE) and Thai–English bilingual (TE) speakers' ability to perceive word-final stops in their native and non-native languages. In the perception experiment, the TE listeners were able to discriminate stop contrasts differing only in place of articulation (/p/–/t/, /p/–/k/, /t/–/k/) in both English and Thai accurately, but the AE listeners' discrimination was accurate only for English. The listeners' discrimination accuracy was differentially influenced by the type of stop contrast they heard. The Thai /p/–/t/ contrast was most discriminable for both groups of listeners, in particular, the AE listeners. Acoustic analyses of the Thai stimuli presented in the perception experiment were conducted in order to search for cues that led to different response patterns for the AE and TE listeners. There was a clear effect of the final stop on the formant trajectories of /a/ and /u/, suggesting that these acoustic differences may be audible to the listeners. The results provide further evidence that first language (L1) transfer alone is insufficient to account for listeners' response patterns in cross-language speech perception and that it is necessary to take into account phonetic realization of sounds and/or the amount of acoustic information contained in the speech signal to predict accuracy with which sound contrasts are discriminated.