[Objectives]  To investigate the effects of a constant indoor, and a variable outdoor, temperature on life history parameters of Spodoptera frugiperda, including growth, development, survival and reproduction. [Methods]  Populations of S. frugiperda were kept at either a constant indoor temperature (27.5 ℃) or a naturally variable outdoor temperature (22-32 ℃) and life tables for each population compiled. [Results]  There was no significant difference in the duration of the egg stage or that of the first larval instar between the two populations. The larval period, the duration of development from egg to adult, and the adult lifespan after the second instar, were significantly longer in larvae kept indoors than in those kept outdoors. Larvae kept indoors also had significantly higher survival and pupation rates than those kept outdoors. Significantly fewer females were produced indoors than outdoors. The average generation periods under indoor and outdoor conditions were 38.10 and 30.01 d, respectively, the net value-added rates (R₀) were 152.13 and 81.59, the intrinsic growth rates (r) were 0.13 and 0.14, and the cycle-limited growth rates (λ) were 1.14 and 1.15. [Conclusion]  S. frugiperda kept at a constant temperature indoors had a higher survival rate than those exposed to naturally variable outdoor temperatures, but the generation time of the latter was shorter, its fecundity was higher, and the proportion of females produced was greater. Life tables can reveal the effects of variable vs constant temperature on the growth, survival and reproduction of S. frugiperda populations, providing a theoretical basis for obtaining early warning of outbreaks of this pest.