Updated project metadata. Ribosomes have long been thought of as homogeneous macromolecular machines, but recent evidence suggests they are heterogeneous and could be specialised to regulate translation. Here, we have isolated ribosomal complexes and characterised their protein content across 4 tissues of Drosophila melanogaster via TMT-MS. We find that testes and ovaries contain the most heterogeneous ribosome populations, which occurs through a combination of ribosomal protein paralog-enrichment and ribosomal protein paralog-switching. We have also solved structures of ribosomes isolated from tissues by cryo-EM, revealing differences in precise ribosomal arrangement for testis and ovary 80S ribosomes. Differences in the amino acid composition of paralog pairs and their localisation on the ribosome exterior indicate paralog-switching could alter the ribosome surface, enabling different proteins to regulate translation. One testis-specific paralog-switching pair is also found in humans, suggesting this is a conserved site of ribosome heterogeneity. Overall, this work allows us to propose that mRNA translation might be regulated in the gonads through ribosome heterogeneity, providing a potential means of ribosome specialisation.