The periodontium is composed of both soft and hard tissues, thus hard tissue regeneration is one of the most important processes in periodontal regeneration. Bone sialoprotein, osteocalcin, osteopontin and osteonectin are noncollagenous matrix proteins which play vital roles in the mineralization of hard tissue. Recent studies have demonstrated that acemannan, a polysaccharide extracted from Aloe vera gel, upregulated the expression of proteins involved in hard tissue regeneration. This study investigated effect of acemannan on bone sialoprotein, osteocalcin, osteopontin and osteonectin expression in human periodontal ligament cells. Primary periodontal ligament cells were isolated from impacted third molars and then treated with acemannan in vitro. The mRNA expression of bone sialoprotein and osteocalcin and the protein levels of osteopontin and osteonectin were determined using reverse transcription-polymerase chain reaction and western blot analysis, respectively. One-way analysis of variance and Dunnett multiple comparisons were performed to analyze the data. The results revealed that acemannan significantly increased the in vitro expression of bone sialoprotein, osteocalcin, osteopontin and osteonectin, which were 1.4, 1.2, 3.3 and 3.6 fold higher compared with the untreated control group, respectively. Our data indicate that acemannan is a bioactive molecule that can induce the expression of the non-collagenous matrix proteins; bone sialoprotein, osteocalcin, osteopontin and osteonectin in periodontal ligament cells.