To explore the expression pattern, prognostic value and functional role of stromal periostin (POSTN) in glioma patients, POSTN expression was measured using the Agilent Whole Human Genome Oligo Microarray in 220 frozen glioma tissues. We analyzed POSTN expression in 71 independent validated glioma samples using immuno-histochemistry. The expression levels of POSTN were relative to glioma grade progression and inversely correlated with overall survival in high-grade glioma patients (anaplastic gliomas and glioblastomas). Gene ontology (GO) analysis performed using DAVID showed that the gene sets related to cell migration and proliferation were significantly enriched in the cases with POSTN overexpression. Functional analyses in LN229 and U87 cells revealed that POSTN was involved in cell invasion and proliferation. MMP-9 was an effector of POSTN signaling in glioma cells. The expression of stromal protein POSTN is relative to glioma grade progression and confers a poor prognosis via promoting cellular invasion and proliferation in high-grade glioma patients.