In the face of uncertainty and disagreement about the meaning and measurement of the self-monitoring construct, the author proposes an implicit theories approach to shed light on what self-monitoring scales may be tapping. The first study explored people's notions of what high and low self-monitors are like, based on the statements in the 18-item Self-Monitoring Scale (Gangestad and Snyder, 1985). The second study compared that measure with Lennox and Wolfe's (1984) Revised Self-Monitoring Scale and examined defensive motivation within the scales. The third study consisted of two experiments to determine whether subjects perceived the items of Gangestad and Snyder's Self-Monitoring Scale as reflecting a unitary latent entity or separate, contradictory variables. It was concluded that the implicit theories approach appears to be a useful complement to traditional factor analytic studies, providing new ways of looking at a personality construct, clarifying some theoretical issues, and generating hypotheses for future research.