Heterogeneous nuclear ribonucleoprotein K (hnRNPK) is a multifunctional protein that plays a significant role in various cellular processes. It is involved in a wide range of biological processes such as transcription, translation, splicing, chromatin remodeling, and signal transduction. It can interact with numerous nucleic acids and various proteins, influencing cellular functions like proliferation, differentiation, apoptosis, DNA damage repair, and stress and immune responses. HnRNPK has been implicated in the development and progression of various diseases, particularly in cancer. It can act as an oncogene, being overexpressed in cancer tissues compared to non-neoplastic tissues, and its expression level is related to the prognosis of different types of malignancies. However, it has also been identified as a tumor suppressor, important for the activation of the p53/p21 pathway. HnRNPK may play a role in regulating 3'-end RNA processing and transcription termination, particularly through its interaction with the 5'-3' exonuclease XRN2. HnRNPK has been found to be related to the regulation of long noncoding RNAs (lncRNAs) such as Neat1, Lncenc1, and Xist, which are involved in various cellular events, including cancer development. Interestingly, hnRNPK has also been associated with skeletal abnormalities and is essential for the formation of osteoclasts, highlighting its importance in the skeletal system.