This thesis examined how receivers who vary in Interaction Involvement and Locus of Control (LOC) might differ in their interpretations of service complaints. Locus of control was measured using Rotter's (1966) LOC scale, while Interaction Involvement was measured with Cegala's (1984) Interaction Involvement measure, including a separate assessment of the effects for each sub-scale. Individuals were assigned to four groups based on their Interaction Involvement and LOC scores. The groups were compared with one-another for differences in how complaints were interpreted. Four complaint categories and a corresponding scale were developed to measure these differences. The categories were Subject, Goal, Opportunity, and Accountability. Interaction Involvement was expected to affect how receivers interpret the subject and goal of a complaint, while LOC was predicted to affect understanding of the opportunity and accountability aspects. Two research questions explored possible relationships between the complaint categories and the independent variables for individuals within each group. The study's four hypotheses were not supported, although some evidence was found for a significant relationship between receiver Interaction Involvement and perceived complainant Opportunity, for External LOC individuals only.