An electrical connector includes a plug and a sliding lock element. The plug includes an inserting portion, a cover portion, and a first sidewall portion. The cover portion covers one end of the inserting portion. The first sidewall portion is perpendicularly connected to the cover portion. A gap is formed between the first sidewall portion and the inserting portion. The sliding lock element is assembled on the plug. The sliding lock element includes a lid portion, a vertical extension portion, and a fitting portion. The lid portion slidably covers the cover portion of the plug. The vertical extension portion is perpendicularly connected to the lid portion. The fitting portion is connected to the vertical extension portion and extends toward the lid portion.