Recent studies in the acquisition of a second language (L2) phonology have revealed that orthography can influence the way in which L2 learners come to establish target-like lexical representations (Escudero et al., 2008, 2014; Escudero and Wanrooij, 2010; Showalter, 2012; Showalter and Hayes-Harb, 2013). Most of these studies, however, involve language pairs relying on Roman-based scripts. In comparison, the influence of a foreign or unfamiliar written representation on L2 phonological acquisition remains understudied. The present study therefore considers the effects of three L2 scripts on the early acquisition of an Arabic consonantal contrast word-initially (e.g. /hal/-/?al/). Monolingual native speakers of English with no prior knowledge of Arabic participated in a word-learning experiment where they were instructed to learn six pairs of minimally contrastive words, each associated with a unique visual referent. Participants were assigned to one of four learning conditions: no orthography, Arabic script, Cyrillic script, and Roman/Cyrillic blended script. After an initial learning phase, participants were then tested on their phonological knowledge of these L2 minimal pairs. The results show that the degree of script unfamiliarity does not in itself seem to significantly affect the successful acquisition of this particular phonological contrast. However, the presence of certain foreign scripts in the course of phonological acquisition can yield significantly different learning outcomes in comparison to having no orthographic representation available. Specifically, the Arabic script exerted an inhibitory effect on L2 phonological acquisition, while the Cyrillic and Roman/Cyrillic blended scripts exercised differential inhibitory effects based on whether grapheme-phoneme correspondences activated first language (L1) phonological units. Besides revealing, for the first time, that foreign written input can significantly hinder learners' ability to reliably encode an L2 phonological contrast, this study also provides further evidence for the irrepressible hold of native orthographic rules on L2 phonological acquisition.