NIR (JHK) photometry of six quasars with redshifts ranging from 3 to 3.78 is reported. None of these objects has previously been observed in the IR. Their NIR colors are bluer than those of low-redshift quasars. They do, however, exhibit a considerable scatter, which can be qualitatively explained by line-emission contamination within the IR bandpasses. For a larger sample of quasars with redshifts greater than 2.5, the J-H and H-K color indices show opposite trends in their respective color vs redshift diagrams. These opposite trends, and the fact that the J-K colors exhibit no clear redshift dependence suggest that any trends of the continuum of quasars that might point to some kind of evolutionary effects, if present, are at a level that is completely hidden by contamination of the IR bands by quasar emission lines.