Context: Although Agile Software Development (ASD) has proven to be an important set of methods that promotes simplicity issues, there are difficulties in defining simplicity. Purpose: To develop a conceptual framework of simplicity from the agile teams perspective. Method: A literature review was conducted covering models related to simplicity in different research areas. Based on that, a conceptual framework was developed, which was then triangulated through a focus group with six ASD experts. Results: Five simplicity perspectives in the context of ASD were identified. From the agile teams perspective, simplicity is defined as the theoretical virtue disposing the team towards an analytic attitude that leads agile projects to be successful. Conclusion: The conceptual framework of simplicity in agile software development is an invitation to practitioners to do what they already do, but to do so more consciously. This consciousness can make a substantial difference in real situations.