A high definition multimedia interface (HDMI) socket for fastening on a metallic chassis includes a main body, a connecting member and a plastic piece. The connecting member includes a slot portion and a bent portion. The slot portion has a first and a second ends. The first end is connected with the main body. The bent portion is connected with the second end and has a first abutting surface abutting against the inner surface. The plastic piece is connected with the main body and has two second abutting surfaces. When the first abutting surface abuts against the inner surface before the plastic piece is fastened on the metallic chassis, a gap exists between the second abutting surfaces and the inner surface. When the plastic piece is fastened on the metallic chassis, the plastic piece is deformed and the second abutting surfaces abut against the inner surface.