PURPOSE: This study aimed to investigate treatment effects of naming therapy targeting nouns and verbs in Mandarin-English bilingual adults with aphasia (BWA). METHOD: Twelve Mandarin-English bilingual adults with chronic aphasia completed a 40-hr semantic-based naming treatment for either nouns or verbs. Eight of these participants completed both noun and verb treatment, and the other four completed either noun or verb treatment. Participants were trained in either Mandarin or English for both treatment cycles. Weekly naming probes were measured to capture the direct treatment gain and within- and cross-language generalizations. Performance on the standardized language assessments was analyzed to examine further generalizations beyond the word level and to standardized naming tasks. RESULTS: Responses in the weekly naming probes showed significant treatment gains in both noun and verb treatment, but the effect was greater in verb treatment. Generalization to semantically related items was captured in noun treatment only. Cross-language generalization was identified in both noun and verb treatment with a larger effect in verb treatment. Additionally, widespread generalizations beyond the word level and to standardized naming tasks were found following both noun and verb treatment, but the effect was larger following noun treatment in discourse and verb naming tasks. CONCLUSIONS: Findings from this study suggested robust treatment effects of semantic-based naming treatment targeting nouns and verbs in Mandarin-English BWA. However, patterns of treatment gains and generalizations differed between these word categories. This study provides strong evidence of bilingual aphasia rehabilitation in Mandarin-English BWA.