The earliest stages of pidgin formation show a preference for analytic and morphologically reduced grammatical constructions relative to their lexifier or substrate languages, where the apparent morphological marking, if found, seems to be fossilized. Structural relations, therefore, are mostly expressed externally. Tense/aspect categories are marked through temporal adverbials or inferred from the context. Creole languages, however, are said to develop such categories through grammaticalization. This study examines tense/aspect marking in five Arabic-based pidgins: Juba Arabic, Turku Pidgin, Pidgin Madame, Romanian Pidgin Arabic, and Gulf Pidgin Arabic. Using Siegel's (2008) scale of morphological simplicity, from lexicality to grammaticality, this study concludes that tense/aspect marking is expressed lexically through temporal adverbials or inferred from the context in the earliest stages of Arabic-based pidgins, which only later—in stabilized pidgins—develops into grammaticalized markers when certain criteria are met.