A system described herein may provide for the prioritization of Session Initiation Protocol (“SIP”) messages, transmitted by a User Equipment (“UE”), based on a priority class indicator included in the SIP messages by the UE. A Universal Integrated Circuit Card (“UICC”) may store information indicating the priority class (e.g., in an Access Control Class (“ACC”) Elementary File (“EF”)). One or more network components, such as a Call Session Control Function (“CSCF”) and/or a Messaging Application Server (“MAS”) may prioritize the SIP message based on the priority class indicator included in the SIP message by the UE.