Aims: The study investigates the effects of L2 proficiency and L2 exposure on L2-to-L1 cross-language activation (CLA) in L1-dominant bilinguals. In so doing, it tests the predictions made by prominent models of the bilingual lexicon regarding how language experience modulates CLA. Design: The participants (27 L1-dominant L1 English–L2 Afrikaans speakers) completed a visual world eye-tracking task, conducted entirely in English, in which they saw four objects on a screen: a target object, which they were instructed to click on; a competitor object, whose Afrikaans label overlapped phonetically at onset with the English target object label; and two unrelated distractors. Language background data were collected using the Language History Questionnaire 3.0. Analysis: A growth curve analysis was performed to investigate the extent to which the background variables modulated looks to the Afrikaans competitor item versus to the two unrelated distractor items. Findings: Increased L2 exposure was associated with greater CLA, which is consistent with models suggesting that exposure modulates the likelihood and speed with which a linguistic item becomes activated. Moreover, CLA was reduced at higher levels of L2 proficiency, which aligns with accounts of the bilingual lexicon positing that parasitism of the L2 on the L1 is reduced at higher proficiency levels, leading to reduced CLA. Originality: L2 activation during L1 processing and the variables that modulate it are not well documented, particularly among L1 speakers with limited proficiency in and exposure to the L2. Significance: The findings contribute to the evaluation of competing accounts of bilingual lexical organization.