SUMMARY: We present MitoVisualize, a new tool for analysis of the human mitochondrial DNA (mtDNA). MitoVisualize enables visualization of: (i) the position and effect of variants in mitochondrial transfer RNA and ribosomal RNA secondary structures alongside curated variant annotations, (ii) data across RNA structures, such as to show all positions with disease-associated variants or with post-transcriptional modifications and (iii) the position of a base, gene or region in the circular mtDNA map, such as to show the location of a large deletion. All visualizations can be easily downloaded as figures for reuse. MitoVisualize can be useful for anyone interested in exploring mtDNA variation, though is designed to facilitate mtDNA variant interpretation in particular. AVAILABILITY AND IMPLEMENTATION: MitoVisualize can be accessed via https://www.mitovisualize.org/. The source code is available at https://github.com/leklab/mito_visualize/. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.