The present data paper describes an experimental campaign on five thin T-shaped reinforced concrete walls, including: details on the test units, materials, test setup, loading protocol, instrumentation, main features of each unit's response, organization of the provided test data, and examples of derived data. The tests aimed at assessing the influence of wall thickness on member stability, the role of lap splices on damage distribution and displacement ductility, and the effects of the simultaneous application of out-of-plane loading on the member response. A set of five companion test reports, one for each of the tested units, supplement the present manuscript.