Background The transcription factor 7-like 2 (TCF7L2) is one of the genes that have been identified as possible determinants of diabetes which is associated with obesity. Data on the genetic causes of obesity in sub-Saharan African populations are very scares. The aim of this study was to assess the association between the transcription factor 7-like 2 (TCF7L2) gene polymorphism (rs12255372 G/T) and obesity and weight-related traits in a Cameroonian population. Methods A case–control study was conducted on 35 obese and 30 non-obese Cameroonian adults. TCF7L2 rs12255372 genotypes were determined using PCR–RFLP and correlated with BMI and weight-related traits. Results No significant association was observed between the rs12255372 T allele (χ2 = 0.0684, p = 0.79) or the TT genotype (χ2 = 0.372, p = 0.54) of the TCF7L2 gene and obesity in the Cameroonian population. However, amongst the weight-related traits, triglycerides were significantly associated with the T risk allele of the TCF7L2 gene (p = 0.012). Conclusion This study on Cameroonian subjects replicates the absence of association between the TCF7L2 rs12255372 variant and obesity as observed in European and American populations.