A heat exchanger (100), a heat exchanger module (100′) having the heat exchanger (100), and an air conditioning system having the heat exchanger (100) or the heat exchanger module (100′); the heat exchanger (100) comprises: a first header (11) and a second header (12), with an axis of the first header (11) being inclined relative to an axis of the second header (12); and a heat exchange pipe (2) connected to the first header (11) and the second header (12), the heat exchange pipe (2) being bent. The heat exchange efficiency can be increased by using the heat exchanger (100).