A heat dissipation device adapted for cooling a heat-generating electronic component includes a heat sink (30), a fan (40) mounted on the heat sink (30), a fan duct (70) mounted on the fan (40) and a clip (50) securing the fan duct (70) on the fan (40). The fan (40) is sandwiched between a top of the heat sink (30) and a bottom of the fan duct (70). The clip (70) includes an axis (51) pivotably mounted on to a bottom of the fan duct (70), a locking portion (52) extending from an end of the axis (51) and buckled with the fan duct (70), and a pressing portion (53) bent from the axis (51) and engaging with a bottom surface of the top plate (42) of the fan (40).