As the discovery of functions of long noncoding RNA (lncRNA) HOTAIR lifts ncRNA to new levels, large numbers of research have been demonstrated for the roles of lncRNAs in diverse biological processes, such as development, cellular differentiation, and a wide range of diseases including cancer. And, recent studies have discovered that lncRNAs can participate in almost every step in the life cycle of gene regulation, including chromosome dosage compensation, imprinting, epigenetic regulation, nuclear and cytoplasmic trafficking, transcription, mRNA splicing, and translation, mainly in the four archetypes-signals, decoys, guides, and scaffolds. Unsurprisingly, accumulating studies have demonstrated that serious lncRNAs are dysregulated in gastric cancer (GC), one of the major causes of cancer-related mortality worldwide, and closely related to tumorigenesis, metastasis, or prognosis. In this review, we will discuss diverse functions of lncRNAs and highlight the growing evidence for the important roles of lncRNAs acting as biomarkers for the early diagnosis of GC, as indicators of GC prognosis, or even as therapeutic targets in GC.