A receptacle assembly is configured to be disposed on a circuit board and to receive a pluggable module and includes a cage member and a connector. The cage member includes a housing portion and at least one fin portion. The housing portion defines an accommodation space and an insertion hole in fluid communication with the accommodation space. The insertion hole is located at one end of the accommodation space. The fin portion is integrally formed with the housing portion and extends outwardly from an outer surface of the housing portion. The connector is located at another end of the accommodation space. The insertion hole is configured for an insertion of the pluggable module into the accommodation space and the connector is configured to be electrically connected to the pluggable module.