The role of spectroscopy and atomic physics in the investigation of particle transport in tokamaks is reviewed using experiments that were conducted on the Texas Experimental Tokamak as examples. In one experiment, the parallel particle flow was shown to be directly modified by ion-neutral charge exchange. In another experiment, particle confinement is shown to be correlated with electrostatic turbulence. Spectroscopic techniques were also used to examine a prediction that neutral ionization induces plasma turbulence. Finally, spectroscopy is shown to be applicable to the measurement of plasma turbulence provided sufficient atomic data is available for analysis.