Background: Turkish has a rich system of noun suffixes, and although its complex suffixation system may seem daunting, it can actually present a learning opportunity for children. Despite its unique features, Turkish has not been studied extensively, especially in the case of children with language deficits, such as developmental language disorder (DLD). Most of the extant studies are focused on bilingual children, and the results are somewhat mixed. Aims: To focus on the noun morphology system of Turkish-speaking preschoolers with DLD and compare their use with that of two groups of typically developing (TD) children. Moreover, to investigate the nature of their noun suffix errors in detail. Methods & Procedures: We report data from a total of 80 monolingual children, 40 children with DLD (age range = 4;0-7;10), 20 TD age-matched children (4;0-7;3) and 20 younger mean length of utterance (MLU)-matched children (2;0-4;3). The data for this study came from language samples obtained from children in individual clinical assessment sessions. Outcomes & Results: The children with DLD made less use of noun suffixes than both the younger and the age-matched TD children. The use of the unmarked (nominative case) form in place of an overt suffix was the most likely error by all groups. Suffix-change alternations required beyond vowel harmony seemed to pose real problems for these children. Conclusions & Implications: These results suggest that even when a language appears to provide significant advantages for the learning of noun morphology, children with DLD do not succeed in closing the gap. Certain factors such as morphophonological changes beyond vowel harmony, multiple allomorphs for the same suffix type and accusative suffixes that are not uniformly applied in the adult input were found to be significant predictors of the DLD group's difficulty with noun suffixes. Because these same factors can serve as characteristics of other languages, a child's difficulties might seem to be language specific (e.g., a particular allomorph in the language), but may actually be based on a broader difficulty (e.g., dealing with multiple allomorphs for the same suffix). Accordingly, factors that transcend a single language should be considered during clinical assessment and therapy.