<p>The reversed language dominance effect refers to the situation in which bilingual speakers process their more-proficient language less efficiently than their less-proficient language when switching between the two languages. Previous studies have found that both more-proficient and less-proficient bilinguals exhibit reversed language dominance. However, conclusions about reversed language dominance effect were limited because these studies mainly used a dichotomy to determine levels of second language proficiency. By taking a continuous approach to measuring second language proficiency, the current study was able to describe how the reversed language dominance effect of bilingual individuals changes as proficiency in their second language increases. Language switching ability was assessed in Mandarin-English bilinguals by analyzing picture-naming latency in single-language and mixed-language blocks using a linear mixed model. The results indicated a significant interaction between second language proficiency and language type in the mixed-language block condition, indicating a reversal of language dominance as second language proficiency increases. This suggests that reversed language dominance is most likely to occur in highly proficient bilingual participants, supporting the language-specific selection threshold hypothesis.</p>