RIG-I-like receptors (RLRs) are key sensors of viral infections, mediating the transcriptional induction of type I interferons and other genes that collectively establish an antiviral host response. Recent studies have revealed that both viral and host-derived RNAs can trigger RLR activation, leading to an effective antiviral response but also immunopathology if uncontrolled. This review discusses recent advances in understanding the types of RNA sensed by RLRs in viral infections, malignancies, and autoimmune diseases. It also describes how RLR activity is controlled by host regulatory mechanisms, including RLR-interacting proteins, post-translational modifications, and non-coding RNAs. Finally, it highlights key outstanding questions in the RLR field, such as how knowledge of RLR biology can be translated into new therapeutics.RIG-I-like receptors (RLRs) are key sensors of viral infections, mediating the transcriptional induction of type I interferons and other genes that collectively establish an antiviral host response. Recent studies have revealed that both viral and host-derived RNAs can trigger RLR activation, leading to an effective antiviral response but also immunopathology if uncontrolled. This review discusses recent advances in understanding the types of RNA sensed by RLRs in viral infections, malignancies, and autoimmune diseases. It also describes how RLR activity is controlled by host regulatory mechanisms, including RLR-interacting proteins, post-translational modifications, and non-coding RNAs. Finally, it highlights key outstanding questions in the RLR field, such as how knowledge of RLR biology can be translated into new therapeutics.