  We report the coexistence of the Kondo effect and spin glass behavior in
Fe-doped NbS$_2$ single crystals. The Fe$_x$NbS$_2$ shows the resistance
minimum and negative magnetoresistance due to the Kondo effect, and exhibits no
superconducting behavior at low temperatures. The resistance curve follows a
numerical renormalization-group theory using the Kondo temperature $T_K
=12.3$~K for $x=0.01$ as evidence of Kondo effect. Scanning tunneling
microscope/spectroscopy (STM/STS) revealed the presence of Fe atoms near sulfur
atoms and asymmetric spectra. The magnetic susceptibility exhibits a feature of
spin glass. The static critical exponents determined by the universal scaling
of the nonlinear part of the susceptibility suggest a three-dimensional
Heisenberg spin glass. The doped-Fe atoms in the intra- and inter-layers
revealed by the X-ray result can realize the coexistence of the Kondo effect
and spin glass.
