Aim: Resistance of mosquito vectors and harmful effects of chemicals on human and its environment have been major problems encountered in vector control through the use of synthetic insecticides, thus there is a need for alternative insecticides of plant derivatives. This research is aimed at using extracts of Tithonia diversifolia and Momordica charantia against the developmental stages of Anopheles gambiae. Place and Duration of Study: The research was conducted at the Federal University of Technology, Akure, Nigeria between the months of March to June, 2017. Methodology: Larvae and pupae of Anopheles gambiae were reared in the laboratory at ambient temperature of 28±2°C and relative humidity of 75±5%. The leave extracts of T. diversifolia and M. charantia were extracted with methanol and were prepared at concentrations, 0.1%, 0.2%, 0.3%, 0.4% and 0.5%. The larvae and pupae of A. gambiae were exposed to these concentrations of the plant extract for 24 hours. Mortality of the larvae and pupae was monitored and recorded. Probit analysis was used to determine the LC50. Results: Date of this research revealed that at all levels of concentrations, mortality of both the larvae and pupae of this insect increased with increase in the concentrations regardless the type of plant extract used.  The leave extract of T. diversifolia having a lower value of LC50 (larvae: 0.20%; Pupae: 0.27%) was more potent than extract from M. charantia having a higher value of LC50 (larvae: 0.31%; Pupae: 0.44%) after 24 hours Post Treatment of larvae and pupae of A. gambiae. T. diversifolia had significant effect on the larvae of A. gambiae with percentage mortality ranges from 23.33-100% within 24 hrs of exposure when compared with M. charantia that had 16.67-100% of mortality larvae of A. gambiae. Conclusion: The obtained results from this research revealed that extracts from the two plants exhibited great insecticidal properties against larvae and pupae of A. gambiae. Therefore, more exploration on the use of these plants for the development of insecticides at commercial level should be done.