While social capital has been extensively studied for its positive effects, its potential risks have received limited attention. This research addresses this gap by examining how social capital constrains job autonomy and subsequently hinders product innovation. Data were collected from 1,007 respondents at 102 Chinese high-tech small and medium-sized enterprises (SMEs), and analyzed using multilevel structural equation modeling. Our findings highlight that social capital negatively impacts product innovation by reducing job autonomy. From a managerial perspective, the findings identify the need for managers to carefully evaluate the trade-offs between the benefits and risks of fostering social capital in the workplace