We calculate in chiral perturbation theory the parity-violating two-pion exchange nucleon-nucleon potentials at leading one-loop order. At a distance of $r={m}_{\ensuremath{\pi}}^{\ensuremath{-}1}\ensuremath{\simeq}1.4$ fm they amount to about $\ifmmode\pm\else\textpm\fi{}16%$ of the parity-violating $1\ensuremath{\pi}$ exchange potential. We evaluate also the parity-violating effects arising from $2\ensuremath{\pi}$ exchange with excitation of virtual $\ensuremath{\Delta}(1232)$ isobars. These come out to be relatively small in comparison with those from diagrams with only nucleon intermediate states. The reason for this behavior, which is opposite that of the parity-conserving case, is the blocking of the dominant isoscalar central channel by CP invariance. Furthermore, we calculate the $T$ matrix related to the iteration of the parity-violating $1\ensuremath{\pi}$ exchange with the parity-conserving one. The analytical results presented in this work can be easily implemented into calculations of parity-violating nuclear observables.