IT outsourcing practices have recently proliferated an interest in service level agreement (SLA) negotiation relevant to engagements with either in-house or external IS service providers. An important research gap exists in establishing Negotiation Support System (NSS) requirements for the processes associated with SLA development. A first step in specifying such requirements is to examine relevant theoretical bases to identify and postulate reasonable propositions. A second step is to examine the efficacy of the theory-based propositions using the constructs adapted in the context of a relevant, practical and exploratory scenario. Accordingly, this paper discusses propositions that rely on theoretical bases from relevant sociological models, it identifies constructs adapted from prior Theory W research in NSS as an exemplar, it discusses an exploratory study related to the research gap identified, and it discusses findings that represent a starting point for identifying SLA NSS requirements.