  We present models for the three-point correlation function (3PCF) of both
dark matter and galaxies. We show that models based on the halo model can
reasonably match the dark matter 3PCF obtained from high-resolution $N$-body
simulations. On small scales ($r\la 0.5\mpch$) the 3PCF is sensitive to details
regarding the density distributions of dark matter haloes. On larger scales ($r
\ga 2.0\mpch$) the results are very sensitive to the abundance of the few most
prominant haloes. Using the conditional luminosity function, we also construct
models for the 3PCF of galaxies, which we test against large mock galaxy
samples. The bias of the galaxy distrubution with respect to the dark matter,
and the finite number of galaxies that can be hosted by individual haloes,
significantly reduce the normalized three-point correlation function with
respect to that of dark matter. Contrary to the 3PCF of the dark matter, the
galaxy 3PCF is much less sensitive to details regarding the spatial number
density distribution of galaxies in individual haloes or to the abundance of
the few most massive systems. Finally, we show that our model based on the
conditional luminosity function is in good agreement with results obtained from
the 2-degree Field Galaxy Redshift Survey. In particular, the model nicely
reproduces the observational finding that the 3PCF for early-type galaxies is
slightly higher than that of late-type galaxies, and that there is no
significant dependence of the 3PCF on galaxy luminosity.
