There is ample evidence that native and non-native listeners use lexical knowledge to retune their native phonetic categories following ambiguous pronunciations. The present study investigates whether a non-native ambiguous sound can retune non-native phonetic categories. After a brief exposure to an ambiguous British English [l/ɹ] sound, Dutch listeners demonstrated retuning. This retuning was, however, asymmetrical: the non-native listeners seemed to show (more) retuning of the /ɹ/ category than of the /l/ category, suggesting that non-native listeners can retune non-native phonetic categories. This asymmetry is argued to be related to the large phonetic variability of /r/ in both Dutch and English.