Rather than random degradation products, the 18 to 40 nucleotides (nt) transfer RNA-derived small RNAs (tsRNAs) are RNA species generated specifically from pre-RNAs or mature tRNAs in archaea, bacteria and eukaryotes. Recent studies from animal systems have shown that tsRNAs are important non-coding RNAs that regulate gene expression at the transcriptional and/or post-transcriptional levels. They are involved in various biological processes, such as cell proliferation, tumor genesis, stress response and intergenerational epigenetic inheritance. In this review, we will summarize the discovery, biogenesis, and function of tsRNAs in higher plants. In addition, analysis on tsRNAs from lower plants is shown.