This study identifies a new family of bacterial ribosome hibernation factors, named Balon, in the cold-adapted bacterium *Psychrobacter urativorans*. Balon is a distant homologue of archaeo-eukaryotic translation factors aeRF1 and Pelota, and is found in 20% of studied bacteria. During cold shock or stationary phase, Balon occupies the ribosomal A site in both vacant and actively translating ribosomes, bound to EF-Tu. This binding is mRNA-independent, allowing Balon to initiate ribosome hibernation even when ribosomes are engaged in protein synthesis. Balon's unique mechanism of binding to ribosomes, its ubiquitous presence in bacteria, and its role in ribosome hibernation suggest that it represents a novel and widespread mechanism of stress response in bacteria. The discovery of Balon also highlights the need to revise current models of ribosome hibernation, which were largely inferred from studies in model organisms like *Escherichia coli*.This study identifies a new family of bacterial ribosome hibernation factors, named Balon, in the cold-adapted bacterium *Psychrobacter urativorans*. Balon is a distant homologue of archaeo-eukaryotic translation factors aeRF1 and Pelota, and is found in 20% of studied bacteria. During cold shock or stationary phase, Balon occupies the ribosomal A site in both vacant and actively translating ribosomes, bound to EF-Tu. This binding is mRNA-independent, allowing Balon to initiate ribosome hibernation even when ribosomes are engaged in protein synthesis. Balon's unique mechanism of binding to ribosomes, its ubiquitous presence in bacteria, and its role in ribosome hibernation suggest that it represents a novel and widespread mechanism of stress response in bacteria. The discovery of Balon also highlights the need to revise current models of ribosome hibernation, which were largely inferred from studies in model organisms like *Escherichia coli*.