Using data from Chinese A-share listed companies from 2010 to 2021, we examined the impact of ESG rating disagreement on stock price synchronicity and its mechanisms. We discovered that ESG rating disagreement increases stock price synchronicity by raising investors' information costs and reducing the efficiency of ESG information incorporation into prices. This effect is more pronounced when average ESG ratings are either low or high. Our findings highlight how ESG rating disagreement affects stock price synchronicity and provide insights for regulators to standardize rating criteria and foster a conducive ESG investment environment, promoting pricing efficiency in the capital markets.