A heat dissipation device for at least a heat-generating electronic component includes a heat sink, a fan for providing an airflow through the heat sink and a fan holder coupling the fan to the heat sink. The heat sink has a first locking part and a second locking part opposite to the first locking part. The fan holder has a first engaging part engaging with the first locking part at one side of the heat sink and a second engaging part engaging with the second locking part of the heat sink at an opposite side thereof. The first engaging part has a horizontally extending fixing arm and a barb extending downwardly from the fixing arm and hooking with a top side of the heat sink.