During our search for anti-tumor agents from pteridophytes, three new flavonoids, protoapigenone (1), 5′,6′-dihydro-6′-methoxyprotoapigenone (2), and protoapigenin (3), along with four known compounds, protoapigenin 4′-O-β-D-glucoside (4), apigenin 4′-O-β-D-glucoside (5), kaempferol 3-O-α-L-rhamnopyranoside (6), kaempferol 3,7-di-O-α-L-rhamnopyranoside (7), were isolated from Thelypteris torresiana using bioactivity-guided fractionation methods. The structures of the new isolates were elucidated by 1D- and 2D-NMR spectral analysis. Among the 7 compounds, protoapigenone (1) exhibited significant anti-tumor activities toward Hep G2, Hep 3B, MCF-7, A549, and MDA-MB-231 with IC50 values of 1.60, 0.23, 0.78, 3.88 and 0.27 μg/mL, respectively.