Apparatuses, methods, and computer readable media are disclosed for fragmentation of media access control service data units (MSDU) in a high-efficiency wireless local-area network. An apparatus of a access point or station comprising memory and processing circuitry coupled to the memory is disclosed. The processing circuitry is configured to fragment a media access control (MAC) service data unit (MSDU) into two or more MSDU fragments, and encapsulate the two or more MSDU fragments into two or more aggregated MSDUs (A-MSDUs); one or more A-MSDUs and one or more MAC protocol data units (MPDUs); or, two or more MPDUs. The processing circuitry may be further configured to encode a delimiter in front of a first fragment of the two or more MSDU fragments, where the delimiter indicates a length of the two or more MSDU fragments, and to encode each MPDU to comprise a sequence number.