Summary Individual differences in episodic memory abilities have been linked to second language (L2) lexical development, both theoretically and empirically, but such empirical support has been limited to the earliest phases of word learning. However, the Episodic L2 Hypothesis predicts that L2 lexical representations in more advanced L2 speakers are episodic in nature. To examine whether this means that individual differences in episodic memory also contribute to higher level L2 lexical abilities, we examined whether episodic memory abilities were predictive of lexical knowledge in a group of higher proficiency L2 learners who had years of exposure to their L2. The results revealed that episodic memory abilities predicted L2 lexical knowledge, a finding with pedagogical consequences. Moreover, these findings are consistent with several neurocognitive theories of the mental lexicon, and the Episodic L2 Hypothesis in particular.