What motivates language teachers to pursue professionalization? Using the American example of National Board certification, this study examined the strength and interrelationships of five motivational factors for foreign language teacher professionalization: improved teaching, financial gain, internal validation, external validation, and collaboration. A total of 433 foreign language teachers participated in the online survey. Repeated measures ANOVAs found improved teaching, financial gain, and internal validation were strong motivations, whereas the other two were less strong or weaker motivations. Additionally, correlational analyses showed a negative correlation between the two highest motivations, improved teaching and financial gain, indicating that they may represent two distinguishing motivational dimensions. These findings dispute teachers’ supposed lack of extrinsic motivations and support a continuum of motivations for professionalization, as seen in the types of extrinsic motivations in Self- Determination Theory.