A growing body of literature has explored issues surrounding the maintenance and development of a minority heritage language among immigrants and their children in relation to their ethnic identities in multi-ethnic societies. However, most of the studies either have alluded to heritage learners' language competence by way of their attitudes and ideologies toward their heritage and language maintenance or have addressed their competence by way of self-assessment measures alone. This study examines the interrelationship between Korean heritage learners' perceived and actual competence in Korean vis-a-vis their ethnic identity orientation. Thirty second-generation Korean-American participants completed questionnaires on their language background, ethnic identity orientation, and self-assessment of their speaking and writing skills in Korean. Their speech and writing samples in Korean were elicited with picture stimuli. Results suggest that there was a strong correlation among the subjective and objective assessment of the heritage learners' Korean language skills and their Korean ethnic identity. It was also suggested that the heritage learners who have a strong Korean identity tend to have better competence in Korean, meaning that the strong Korean identity serves as a self-enhancing bias in their self-assessment of the Korean language. (Contains 3 tables and 1 figure.)