  We present calculations of $\gamma^\ast N \to N^\ast$ transition form
factors, where $N$ is the nucleon and $N^\ast$ is a nucleon resonance, based on
a covariant quark model. Our main focus is at high photon virtualities (large
$Q^2$) where the valence quark degrees of freedom dominate the contributions to
the transition form factors and helicity amplitudes. In that regime, the quark
model estimates can be compared with the available data, particularly with the
Jefferson Lab data at intermediate and large momentum transfer ($Q^2 >2$
GeV$^2$). The main focus is on the $\Delta(1232)3/2^+$, $N(1440)1/2^+$,
$N(1535)1/2^-$ and $N(1520)3/2^-$ resonances, but estimates for other higher
mass resonances are also discussed.
