  In this paper, we consider a one-loop thermal correction to the $g$-factors
of the ground and low-lying excited states in neutral alkaline-like atomic
systems. As an example, we carried out calculations for Rb and Cs atoms, where
optical measurements of transition frequencies set the metrological level of
accuracy. With the development of atomic systems as the most accurate tool for
spectroscopic experiments, it has become increasingly important to improve the
accuracy of measuring the electron $g$-factor, which is currently at
~$10^{-12}$. The rapid progress in this field in recent years requires analysis
not only of various relativistic, QED and other effects, but also theoretical
studies of phenomena stimulated by the external thermal environment. We can
expect that the thermal contribution to the $g$-factor calculated in our work
may be of interest in the near future.
