The eukaryotic cytoplasmic ribosome is essential for protein synthesis and is therefore vital for the development and survival of organisms. The ribosome is made up of 4 rRNAs and approximately 80 ribosomal proteins. Developmental phenotypes of ribosomal protein mutants in plants and animals suggest ribosomal proteins and the ribosome regulate developmental processes, although how this occurs is not known. In Arabidopsis thaliana, cytoplasmic ribosomal proteins are encoded by small gene families containing between two and five paralogs of the ribosomal protein gene. One such gene family, coding for RPL24, contains two ribosomal protein genes, RPL24A and RPL24B. Mutations in the RPL24B gene have been shown to affect female fertility in Arabidopsis by reducing the number of viable ovules. We show that the defective ovules present in the rpl24b mutant display arrested germ-line development. However, genetic analysis indicates that it is the genotype of somatic non-reproductive cells affecting fertility. We propose that RPL24 is involved in signalling between somatic and reproductive cells and that maintenance of this signalling is essential for fertility. Further understanding of the role of ribosomal proteins in fertility and identification of the inter-tissue signal that affects fertility may enable manipulation of plant sterility or induction of apomixis, which would be of major importance to agriculture.