  Dwarf galaxies are ideal laboratories to test dark matter models and
alternative theories because their dynamical mass (from observed kinematics)
largely outweighs their baryonic mass (from gas and stars). In most
star-forming dwarfs, cold atomic gas forms regularly rotating disks extending
beyond the stellar component, thus probing the gravitational potential out to
the outermost regions. Here I review several aspects of gas dynamics in dwarf
galaxies, such as rotation curves, mass models, and noncircular motions.
Star-forming dwarfs extend the dynamical laws of spiral galaxies to lower
masses, surface densities, and accelerations. The three main dynamical laws of
rotation-supported galaxies point to three distinct acceleration scales, which
play different physical roles but display the same value, within uncertainties.
The small scatter around these dynamical laws implies a tight coupling between
baryons and dark matter in galaxies, which will be better understood with
next-generation surveys that will enlarge current sample sizes by orders of
magnitude.
