From the aerial parts of Gutierrezia microcephala (Asteraceae), four oxyflavones were isolated, namely 5,7,2′-trihydroxy-3,6,8,4′,5′-pentamethoxyflavone (1); 5,7,4′-trihydroxy-3,6,8-trimethoxyflavone (2); 5,7,2′,4′-tetrahydroxy-3,6,8,5′-tetramethoxyflavone (3); 5,2′-dihydroxy- 3,6,7,8,4′,5′-hexamethoxyflavone (4), and an ent-clerodane, bacchabolivic acid (5). Compounds 1-5, the synthetic methyl ester (6 ), n-hexane and MeOH extracts were evaluated against the fall armyworm (Spodoptera frugiperda). Gedunin, a known insect growth regulator isolated from Cedrela spp. was used as a positive control. When tested for activity on neonate larvae into the no-choice artificial diet bioassay, flavone (1), clerodane (5), its methyl ester (6), MeOH and n-hexane extracts caused significant larval mortality with MC 50 of 3.9, 10.7, 3.46. 7.95 and 7.5 ppm at 7 days, respectively, as well as growth reduction. They also increased the development time of surviving larvae and a significant delay in time to pupation and adult emergence. Acute toxicity against adults of S. frugiperda was also found, 5, 6 , gedunin and n-hexane extract had the most potent activity with LD 50 value of 6.59, 15.05, 10.78, and 12.79 ppm, respectively. In addition, MeOH, n-hexane extracts, 5, 6 and gedunin caused acetylcholinesterase inhibition with 93.7,100,90.2,62.0 and 100% at 50.0 ppm, respectively; whereas 1-4 exhibited only moderate inhibitory activity. Compounds 1,5 and 6 showed inhibitory activities comparable with gedunin. These compounds could be responsible of the insect growth inhibitory activity of this plant.