Introduction Waist-to-height ratio (WHtR) is increasingly being reported as a simple, but accurate measure of cardiometabolic risk, even better than BMI, WHR and even waist circumference. Therefore, the objective of this study was to determine the cardiometabolic risk using WHtR, and its association with dietary diversity, activity patterns and the nutritional status of workers in tertiary educational institutions in Southwestern Nigeria. Materials and Methods This was a descriptive cross-sectional study carried out among workers in 3 randomly selected tertiary educational institutions in Osun State, Nigeria who were adults (18 years and above). Only apparently healthy people were recruited for the study. Cardiometabolic risk was assessed using WHtR, and respondents were categorized into low risk (WHtR < 0.5) or high risk (WHtR ≥ 0.5). Bivariate and multivariate (logistic regression model) analyses were used to determine the significant predictors of cardiometabolic risk. Level of significance was set at p-value less than 0.05. Results The mean age of the respondents was 45.8 ± 10.4 years, with a male:female ratio of 1:1.1. The mean WHtR among the respondents was 0.53 ± 0.08, and 36.5% had low cardio-metabolic risk while 63.5% had high cardiometabolic risk. The prevalence of overweight and obesity were 44.0% and 25.8% respectively using the BMI categories. At bivariate level, there were statistically significant associations between WHtR and age (p < 0.001), gender (p = 0.002), educational level (p = 0.046), marital status (p = 0.022), dietary diversity (p = 0.027) and activity patterns (p = 0.030). When these were entered into a binary logistic regression model, age (p = 0.028; CI = 1.003 to 1.060) and gender (p = 0.010; CI = 1.149 to 2.784) remained the only statistically significant explanatory variables for cardiometabolic risk using WHtR. Conclusion The study found a relatively high prevalence of cardiometabolic risk, overweight and obesity among the respondents, with age and gender being the main predictors of cardio-metabolic risk using WHtR. Therefore, there is a need for early screening for cardiometabolic risk using WHtR, especially among the females.