  General relativity offers a classical description to gravitation and
spacetime, and is a cornerstone for modern physics. It has passed a number of
empirical tests with flying colours, mostly in the weak-gravity regimes, but
nowadays also in the strong-gravity regimes. Radio pulsars provide one of the
earliest extrasolar laboratories for gravity tests. They, in possession of
strongly self-gravitating bodies, i.e. neutron stars, are playing a unique role
in the studies of strong-field gravity. Radio timing of binary pulsars enables
very precise measurements of system parameters, and the pulsar timing
technology is extremely sensitive to various types of changes in the orbital
dynamics. If an alternative gravity theory causes modifications to binary
orbital evolution with respect to general relativity, the theory prediction can
be confronted with timing results. In this chapter, we review the basic
concepts in using radio pulsars for strong-field gravity tests, with the aid of
some recent examples in this regard, including tests of gravitational dipolar
radiation, massive gravity theories, and the strong equivalence principle. With
more sensitive radio telescopes coming online, pulsars are to provide even more
dedicated tests of strong gravity in the near future.

General Relativity and Quantum Cosmology;High Energy Astrophysical Phenomena