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The influence of population origin on the tolerance of Tribolium castaneum to oils of Allium sativum and Dennettia tripetala was investigated in this study. Beetle samples were obtained from four States in Southwestern Nigeria. Insect samples were collected from four different major towns from each State before being pooled together to have a better representation of insect samples from each State. The main and interactive effects of population location, concentration and exposure time on the tolerance of T. castaneum to both botanical extracts were explored. Generally, the nature of botanical insecticide, exposure time and concentration affect the response of beetles to both plant extracts. A. sativum was more toxic to Lagos, Ogun and Oyo State biotypes of T. castaneum than D. tripetala. Lagos State beetle population showed the highest tolerance to both botanical extracts while Ondo and Ogun States biotypes recorded the lowest tolerance to D. tripetala and A. sativum, respectively. There were significant effects (p < 0.0001) of population location (L), concentration (C), exposure time (E) and L×E on the response of beetles to both extracts. This study showed that the geographical location of T. castaneum could considerably influence the degree to which other factors; especially exposure time affects beetle’s mortality when controlling them using extracts from the two plants extracts. KEYWORDS: Allium sativum, biotypes, Dennettia tripetala, geographical location, mortality.