The underutilization of professional care is a perennial problem among Chinese populations. To examine the social-cognitive factors that may affect help-seeking intentions, the present study applied and extended Ajzen’s theory of planned behavior (TPB) to understand the intention to seek help from mental health professionals among Chinese. The effect of mental health and perceived barriers to help-seeking were also examined. Nine hundred and forty-one Chinese were recruited using a randomized household design in Hong Kong. Results from structural equation modeling showed that attitude, subjective norm, perceived behavioral control, and perceived barriers significantly predicted help-seeking intention. Mental health showed no significant effect on help-seeking intention. In addition, subjective norm indirectly predicted intention to seek help from mental health professionals through influencing attitude and perceived behavioral control. Results from multi-group analyses revealed that all path coefficients were invariant across gender. Results supported the utilization of TPB in understanding help-seeking intentions and highlighted the importance of subjective norm among Chinese. Implications on the enhancement of mental health awareness and the promotion of mental health services through a social-cognitive approach were highlighted.