An electronic device and a hinge assembly thereof are provided. The hinge assembly has a first fixing block, a second fixing block, a first linking rod and a second linking rod. The first fixing block has a first end and a second end. The second fixing block has a third end and a fourth end. The first linking rod has a fifth end slidably and rotatably connected to the second end and a sixth end rotatably connected to the fourth end. The second linking rod has a seventh end slidably and rotatably connected to the fourth end and an eighth end rotatably connected to the second end. The sixth end has a groove portion and a first inclined surface, and the eighth end has a second inclined surface contacting the first inclined surface.