Noncoding RNAs (ncRNAs) have become crucial components of gene regulatory networks in numerous plant species. Short noncoding RNAs (sRNAs), specifically 20–30-nucleotide ones, play significant roles in modulating developmental processes and responses to biological stress. Various classes of sRNAs have been identified, and their distinct functions are being characterized based on differences in their biogenesis mechanisms. This article examines the current understanding of major classes of sRNAs, such as microRNAs, small nuclear RNAs (snRNAs), and secondary classes. In eukaryotic genomes, a wide range of ncRNAs, including long ncRNAs (lncRNAs) and microRNAs (miRNAs) are crucial for transcriptional and posttranscriptional control of gene expression. Evidence suggests that these ncRNAs play important regulatory roles in plant stress responses. High-throughput sequencing has revealed that the majority of RNAs lack the ability to code for proteins. lncRNAs are transcripts longer than 200 nucleotides that do not encode proteins. Computational methods have uncovered numerous lncRNAs in various plant species. LncRNAs interact with DNA, RNA, and protein molecules to regulate the expression of their target genes at the epigenetic, transcriptional, posttranscriptional, or translational levels. This chapter provides examples of miRNA and lncRNA-mediated plant stress tolerance mechanisms, discusses lncRNA biogenesis and regulatory processes, and summarizes ongoing research on the identification, characterization, bioinformatics tools, and resources for plant miRNAs and lncRNAs.