BACKGROUND: Both behavioral inhibition system (BIS) and behavioral approach system (BAS) sensitivity have been proposed to play a role in social anxiety; however, findings concerning the relationship between BAS and social anxiety have been mixed. Moreover, recent evidence suggests that low levels of BAS may only be associated with the social interaction subdimension of social anxiety. METHOD: Measures of BIS, BAS, social interaction anxiety, and social observation anxiety were administered to three large analogue samples. RESULTS: As hypothesized, BAS was inversely related to social interaction anxiety, but was unrelated to social observation anxiety across all three samples. In addition, individuals with generalized social fears were found to report both higher levels of BIS and lower levels of BAS compared to individuals with few or specific social fears. CONCLUSION: These findings suggest that a complete motivational account of generalized social anxiety should include both BIS and BAS.