The State-Trait Cheerfulness Inventory (STCI) assesses latent traits and states of cheerfulness, seriousness, and bad mood to represent the temperamental basis of humor. The present study (1) tested the generalizability of the three-factor model in both state and trait versions of the STCI across European Canadian (N = 489) and first generation Chinese Canadian (N = 147) participants completing the English version of the STCI and (2) compared latent mean differences. Results indicated the confirmatory factor analyses of the three-factor model for European White participants born in Canada and Chinese participants born in China showed adequate fit for both trait and state measures. Furthermore, substantial equivalence of factor model parameters and partial scalar invariance were found for both the state and trait STCI measures. In examining latent mean differences, European White Canadian participants reported significantly higher trait cheerfulness, z = 3.30, p < .001, d = 0.84, and lower trait bad mood z = 3.25, p < .01, d = 0.80 compared to the Chinese Canadian groups. European White Canadian participants reported significantly lower state bad mood, z = 3.59, p < .001, d = 1.15, compared to the Chinese Canadian groups. Limitations and future directions based on study findings are discussed.