This study examined the influence of Colloquial Arabic (CA) and English on the use of the definite article by heritage and L2 learners of Standard Arabic (SA). It also investigated the role of typological proximity in language transfer and whether transfer effects change over time. The study involved 149 participants: 73 L2 learners of SA, 61 heritage learners of SA, and 15 native-speaker controls. The participants were from elementary, intermediate and advanced SA courses. The participants completed a fill-in-the-blank task and a translation task. The results indicate that CA plays a facilitative role in heritage learners' use of the definite article. However, English plays both a facilitative and a non-facilitative role for both heritage and L2 learners of SA. In general, typological proximity seems to play a positive role in the use of the definite article in SA. Negative transfer, irrespective of typological proximity, becomes less visible as heritage and L2 learners advance in their study of SA.