  THESEUS is a medium size space mission of the European Space Agency,
currently under evaluation for a possible launch in 2032. Its main objectives
are to investigate the early Universe through the observation of gamma-ray
bursts and to study the gravitational waves electromagnetic counterparts and
neutrino events. On the other hand, its instruments, which include a wide field
of view X-ray (0.3-5 keV) telescope based on lobster-eye focusing optics and a
gamma-ray spectrometer with imaging capabilities in the 2-150 keV range, are
also ideal for carrying out unprecedented studies in time domain astrophysics.
In addition, the presence onboard of a 70 cm near infrared telescope will allow
simultaneous multi-wavelegth studies. Here we present the THESEUS capabilities
for studying the time variability of different classes of sources in parallel
to, and without affecting, the gamma-ray bursts hunt.
