Two novel monoterpenes, sibiscolacton (1) and sibiraic acid (2), were isolated from the aerial part of Sibiraea angustata RCHD: . along with seven known compounds, namely three phenylpropanoids (3-5), two flavonoids (6,7), one glucityl ferulate (8, sibirate), and a monoterpene glucoside (9, sibiskoside). The structures of 1 and 2 were established on the basis of spectroscopic and chemical data.