Non-coding RNAs (ncRNAs) are RNA molecules that do not code for proteins but play crucial roles in regulating gene expression and cellular functions. They include microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and small interfering RNAs (siRNAs), among others. These molecules are involved in processes like transcriptional regulation, RNA splicing, chromatin remodeling, and signal transduction. ncRNAs also contribute to development, immune responses, and disease progression, especially in cancer and neurological disorders. Their regulatory functions make them promising targets for therapeutic interventions.