We show that peer effects influence corporate investment decisions. Using a sample of China’s listed firms from 1999 to 2012, we show that a one standard deviation increase in peer firms’ investments is associated with a 4% increase in firm i’s investments. We further identify the mechanisms, conditions and economic consequences of peer effects in firms’ investment decisions. We find that peer effects are more pronounced when firms have information advantages and the information disclosure quality of peer firms is higher, or if they face more fierce competition. When firms are industry followers, are young or have financial constraints, they are highly sensitive to their peers firms. We also quantify the economic consequences generated by peer effects, which can increase firm performance in future periods. We show that peer effects influence corporate investment decisions. Using a sample of China’s listed firms from 1999 to 2012, we show that a one standard deviation increase in peer firms’ investments is associated with a 4% increase in firm i’s investments. We further identify the mechanisms, conditions and economic consequences of peer effects in enterprises’ investment decisions. We find that peer effects are more pronounced when the firms have ads information quality and the information disclosure quality of peers firms is higher, or if they face more fierce competition are industry followers, are young or have financial constraints, they are highly sensitive to their peers firms. which also increase firm performance in future periods.