A heat sink assembly (100) and a heat sink clip (20) are provided. The heat sink clip (20) includes a pin (22) and a spring (24) disposed around the pin (22). The pin (22) includes an upper section (22a) and a lower section (22b). The upper section (22a) has a head (222) thereon, and the lower section (22a) has a clamping portion (224) and an abutting portion (226) which is located between the head (222) and the clamping portion (224) and is in the form of an annular flange extending radially outwardly from an outer surface of the pin (22). A plurality of slots (22c) are defined through the clamping portion (224) and the lower section (22b) of the pin. The abutting portion (226) engages with a bottom surface of a heat sink (10) before the clip (20) secures the heat sink assembly (100) to a circuit board (40).