This article is based on a data from the first author's master's thesis. Objectives: Culturally diverse family in Korea usually refers to a family consisting of a married Korean citizen and a foreign spouse. Despite the rapid increase of culturally diverse families and acknowledgement of the limited linguistic stimuli for children in those populations, few studies have demonstrated proper research evidence for evaluation and intervention in various language-related areas. Morphological awareness has been recognized as a critical metalinguistic skill relevant to vocabulary acquisition and literacy development. The purpose of this study was to investigate the relation of linguistic competence to morphological awareness of connective endings, one of the unique bound morphemes in Korean, in school-aged Korean-speaking children. Methods: The participants were 38 lower grade children (1st and 2nd grade) and 40 upper grade children (3rd and 4th grade) from three groups: typical children from non-culturally diverse families (TND), typical children from culturally diverse families (TCD) which are language-matched with TND, and language impaired children from culturally diverse families (LCD). Results: The results showed that the significant difference of morphological awareness appeared between TCD and TND in lower grades, but was not found in upper grades. LCD, however, consistently performed lower than TND on the morphological awareness test in both grade levels. Although positive growth in morphological awareness across grades appeared in each of the three groups, LCD remained far below TCD and TND. Conclusion: The study findings revealed that cultural background made a contribution to morphological awareness during the initial period of school years, but longitudinal associations between morphological awareness and linguistic competence lasted even through the late school years.