Cancer is a leading cause of death worldwide, and many of the mechanisms underlying its development remain unclear. But research is beginning to suggest that derivatives of transfer RNA (tRNA) play a role. tRNAs are the most abundant class of RNAs in the human transcriptome and are critical for protein synthesis and cellular metabolism. tRNA-derived fragments (tRFs) are produced by cleaving pre-tRNA and mature tRNA molecules. Previously thought to be random products, tRFs are now known to be functional small non-coding RNA molecules. tRFs are highly conserved and found in many different organisms. Their roles include influencing RNA stability, translation, and gene expression. Now evidence is emerging that suggests tRFs have roles in tumorigenesis and cancer development. Specifically, tRFs may regulate tumor cell proliferation, invasion, migration, and drug resistance. Research into the role of tRFs in cancer is relatively new and requires specialized techniques other than standard high-throughput sequencing. But understanding the mechanisms by which tRFs impact cancer cells could inform malignant tumor diagnosis and treatment, potentially leading to novel prognostic tools and targets for precision cancer therapies.