Ultra- or nano-indentation of thin films provides, in principal, a relatively simple approach to quantify the mechanical properties of thin films. Considerable emphasis has been placed on the ability of pointed indenters to measure such properties. An alternative indentation approach that offers some advantages is the use of very small spherical tipped indenters. The latter provide a more tractable solution to the contact problem. In addition it is possible to follow the elastic to plastic or brittle behaviour during indentation more clearly than with pointed indenters. Greater insight to the actual behaviour of indented materials may be obtained by complementary microstructural observations of the indented region. Finally the role of substrate and interface adhesion on the force-displacement behaviour of thin films indented with spherical tipped indenters is schematically summarized.