Using a sample of A-share private listed companies from 2008 to 2024, this study examines the impact of state-owned capital participation on labor cost stickiness in private enterprises. The results show that state-owned capital participation significantly increases labor cost stickiness, mainly by enhancing labor quantity stickiness rather than wage stickiness. Mechanism analysis indicates that state-owned capital participation exerts this effect by increasing labor adjustment costs and strengthening management’ optimistic expectations. Heterogeneity analysis further reveals that the effect is more pronounced in firms with lower proportions of executive equity incentives and lower human capital intensity. Moreover, the effect is stronger when state-owned shareholders are strategic investors or operators in real-economy industries. The analysis of economic consequences shows that the labor cost stickiness induced by state-owned capital participation contributes to the long-term improvement of private firms’ performance.