Chlamydiae are highly successful strictly intracellular bacteria associated with diverse eukaryotic hosts. Here we analysed metagenome-assembled genomes of the “Genomes from Earth’s Microbiomes” initiative from diverse environmental samples, which almost double the known phylogenetic diversity of the phylum. Our data and analyses provide an extended perspective of the variability of chlamydial biology and the ecology of this phylum of intracellular microbes.