Recently, intriguing new roles for some small nucleolar RNA host genes (SNHGs) in cancer have emerged. In the present study, a panel of SNHGs was profiled to detect aberrantly expressed SNHGs in gastric cancer (GC). The expression of SNHG5 was significantly downregulated in GC and was significantly associated with the formation of a tumor embolus and with the tumor, node and metastasis stage. SNHG5 was a long non-coding RNA, which was a class of non-coding RNA transcripts longer than 200 nucleotides. SNHG5 suppressed GC cell proliferation and metastasis in vitro and in vivo. Furthermore, SNHG5 exerted its function through interacting with MTA2, preventing the translocation of MTA2 from the cytoplasm into the nucleus. SNHG5 overexpression led to significant increases in the acetylation levels of histone H3 and p53, indicating that SNHG5 might affect acetylation by trapping MTA2 in the cytosol, thereby interfering with the formation of the nucleosome remodeling and histone deacetylation complex. This study is the first to demonstrate that SNHG5 is a critical and powerful regulator that is involved in GC progression through trapping MTA2 in the cytosol. These results imply that SNHG5 may be a novel therapeutic target for the treatment of GC.