Non-coding RNAs (ncRNAs) are RNA molecules that are transcribed from DNA but do not code for proteins. Despite not being translated, they play crucial roles in regulating gene expression, genome stability, and various cellular processes. Major types include microRNAs (miRNAs), small interfering RNAs (siRNAs), long non-coding RNAs (lncRNAs), and small nucleolar RNAs (snoRNAs). miRNAs and siRNAs typically regulate gene expression by binding to messenger RNAs (mRNAs) and promoting their degradation or blocking translation. lncRNAs are involved in chromatin remodeling, transcriptional regulation, and RNA splicing. ncRNAs are essential in development, cell differentiation, and disease processes, including cancer and neurological disorders. Advances in molecular biology and genomics have revealed the vast diversity and regulatory potential of ncRNAs, highlighting their importance as therapeutic targets and biomarkers in modern biomedical research.