Submit report handling in Short Message Session Initiation Protocol (SMSIP) is provided. For example, a method can include preparing a submit report, wherein the preparing includes using a combination of forking and an in-reply-to header to find an appropriate terminal. The method can also include sending the submit report to the appropriate terminal. Likewise, another method can include receiving, by an apparatus, a session initiation protocol message request including a submit report. The method can also include processing the submit report to determine whether the request corresponds to a message sent by the apparatus. The method can further include sending, when the submit report is determined not to correspond to any message sent by the apparatus, a not-acceptable-here session initiation protocol response. The method can additionally include sending, when the submit report is determined to correspond to the message sent by the apparatus, an ok session initiation protocol message.