This study evaluated the acute larval toxicity and repellent effect of solvent extracts of the big blue octopus, Octopus cyanea on the mosquito, Culex pipiens. Results showed that the highest effect of the acute larvicidal activities was recorded for ethanol extract (LC50=24.57ppm), followed by methanol extract (LC50=35.85 ppm). The repellency percentages increased with the increase of concentration producing the highest at 200 ppm and 50 ppm for methanol and ethanol extracts, respectively. GC-MS analysis revealed the presence of 19 compounds in ethanol extract and 5 compounds in methanol extract with insecticidal activities. The major identified bioactive compounds are Eugenol; Furoscrobiculin B; Hexadecanoic acid, methylester; Hexadecanoic acid, 1(hydroxymethyl)-1,2-ethanediylester; Octadecanoic acid, methylester; Oleic acid, eicosyl ester; 2-Methyl-5H-dibenz [b, f] azepine and many polysiloxanes compounds. Generally, results obtained indicated that O. cyanea ethanol extract induced remarkable effects on both acute larvicidal and repellent activities.