This study revisits the process of vowel lowering in the Arabic dialect known as Qeltu, which is spoken in parts of northern Iraq and neighboring Syria and Turkey. It aims to uncover hitherto unreported patterns of vowel lowering and re-examines a frequently held axiom that attributes a categorical impact of specific linguistic units on the behavior of this phonological process (e.g. Al-Ani, 1970; Thelwall, 1990; Rose, 1996). The analysis of spoken data from 30 speakers considers various linguistic and social constraints that may or may not influence the process of vowel lowering. The data was collected through sociolinguistic interviews (Tagliamonte, 2006). It is generally acknowledged that the main allophones of Iraqi Arabic [i], [iː], [uː] (Al-Khalesi, 2006) are respectively realized as [a], [ɛː], and [ɔː] in Qeltu (Jastrow, 1994 & 2006). This is especially noticeable when these vowels are adjacent to guttural sounds, as exemplified in the words: /miʃhuːr/ famous, /sˤtˤuːħ/ roof and /daqiːq/ flour, which are pronounced as [maʃhɔːr], [sˤtˤɔ:ħ] and [daqɛ:q], respectively (Jastrow, 1994; Muhammad, 2018). Results indicate that the relationship between guttural sounds and the lowering of vowels in Qeltu cannot be solely predicted by their proximity to each other, and that additional social factors are involved in determining this phenomenon.