Cicadellidae (leafhoppers) may be the most diverse and abundant insect herbivores in terrestrial ecosystems worldwide, with more than 23,000 described species in 20 extant subfamilies. Although prior studies have supported the monophyly of most recognized subfamilies, relationships among these groups remain inconsistently resolved and previous molecular phylogenies have failed to support the monophyly of a few subfamilies. To help address this deficiency, we combined 24 new complete mitogenomes representing 6 previously unsequenced subfamilies and 13 tribes with previously available data to create a dataset of 79 cicadellid taxa representing 16 subfamilies for phylogenetic analysis. The new analyses confirm that leafhopper mitochondrial genomes are highly conservative in overall structure, with only a few rare rearrangements of tRNAs. All phylogenetic analyses consistently supported the monophyly of previously recognized cicadellid tribes for which more than 1 representative was included and all of the included subfamilies were also consistently recovered as monophyletic with the exception of Aphrodinae and Eurymelinae. Bayesian inference and Maximum Likelihood analyses with site-homogeneous models are only slightly affected by nucleotide compositional heterogeneity and yield more stable phylogenetic relationships of family-group taxa than analyses with a heterogeneous-site mixture model using PhyloBayes. Molecular divergence time estimates indicate that the main lineages of Cicadellidae, most corresponding to recognized subfamilies, diverged during the Cretaceous period (93–121 Mya).