An optical fiber connector according to the present disclosure includes a hollow housing, a ferrule holder, a spring, a back post and a sealing ring. The hollow housing has four side walls, wherein two of the four side walls are respectively provided with an opening. An annular bevel is formed in the interior of the housing. The ferrule holder is disposed within the housing. The spring is disposed within the housing to push the ferrule holder. The back post is partially disposed in the housing for abutting on the spring. Two protrusions are formed on the back post and respectively fall in the two openings on the housing. The sealing ring is put on the back post, wherein the back post is configured to push the sealing ring toward the annular bevel inside the housing such that the sealing ring abuts on the annular bevel.