This study examines the impacts of labor protection on stock price synchronicity. I also investigates how the interaction between labor and shareholders affects stock price synchronicity. Using a pooled data from 39 economies over the period 1995- 2011, I find that strong labor protection associates with high stock price synchronicity, which suggests that strong labor protection impedes the informed trading and thus blocks the incorporation of firm-specific information into stock price. Moreover, I find that stock price synchronicity is negatively (positively) associated with the labor protection index in countries with strong (weak) shareholder protection. These findings underline that the interaction between labor and shareholder protection institutions delicately shapes the information environment and stock prices. Overall, my study identifies that labor could exert substantial impacts on stock price synchronicity.