Anecdotal evidence from second language users and results from experimental studies indicate that affectively valent words are not always represented identically in a person’s first language (L1) and second language (L2) mental lexicons. The present study investigated whether such differences reflect how automatic (immediate, involuntary) the processing is of the affective element of affectively valent words, and what the relation is between this kind of processing and general word recognition efficiency for L2 words lacking affective valency. Participants were 48 L1 speakers of English with L2 French. Automaticity of processing adjectives with affective valence was operationalized using an Implicit Affect Association Task (IAAT) developed for this purpose. General efficiency in L2 word recognition was operationalized using a speeded semantic classification task with affectively neutral concrete nouns. Reaction time results from the IAAT showed that the processing of affectively valent words was less automatic in the L2 than in the L1. However, results from the semantic classification task indicated that this effect is not related to general weaker L2 word recognition abilities. Implications for an understanding of the L2 mental lexicon are discussed.