This study examines how English learning influences the self-identity of Vietnamese vocational college students studying English as a foreign language (EFL). A questionnaire survey was conducted with 235 first-year students at Vabis International Vocational College, followed by semi-structured interviews with 10 randomly selected participants. Based on Gao et al.’s (2005) bilingual identity framework, the study investigated six dimensions of identity change: self-confidence, subtractive bilingualism, additive bilingualism, productive bilingualism, identity split, and zero change. The findings show that additive change recorded the highest mean score (M = 3.61), followed by productive change (M = 3.51) and self-confidence change (M = 3.48), while subtractive change remained low (M = 2.10). These results suggest that students were generally able to engage with English while maintaining their Vietnamese cultural identity. Gender-based analysis revealed a statistically significant difference only in subtractive change (p =.000), whereas no significant differences were found in the other dimensions. Overall, the study highlights the predominantly additive and productive nature of identity development in this context.