Background and Objectives: Breakfast skipping has been associated with obesity among adolescents in some studies but little is known about the relationship between breakfast consumption and obesity among secondary-school adolescents in Nigeria. This study contributes to the empirical literature by analyzing the relationship between breakfast consumption and anthropometrically determined nutritional status of secondary-school adolescents in Lagos, Nigeria. Methods: This was a descriptive cross-sectional study in which multi-stage sampling was used to select 397 secondary-school adolescents (10 to 19 years, mean = 13.8 ± 1.7 years). They were classified into student groups from public or private schools in Lagos. Data were collected using a semi-structured self-administered questionnaire and analyzed using Epi-info version 7. The independent variables were the proportion of adolescents who had a high level of knowledge about breakfast consumption, while the outcome variable was the proportion of adolescents who were overweight or obese. World Health Organization (WHO) AnthroPlus software was used to determine the nutritional status of adolescents. Mean and standard deviations were computed for continuous variables, and frequency tables were generated for categorical variables. Significant associations between variables were obtained using Chi-square with the level of significance set at p < 0.05. Results: Only 17% of the adolescents had good knowledge of breakfast consumption. More than half (57.4%) of the participants ate a daily breakfast. The percentage of adolescents who skipped breakfast was higher among older 16-19 years (52.2%) and middle 13-15 years (43%) than the younger adolescents (34.7%). Girls skipped breakfast more than boys. Most respondents were in the normal Body Mass Index (BMI) ranges for their genders. Prevalence of overweight and obesity were 7.1% and 3.3% among males and 7.1% and 2.8% among females respectively. The mean BMI of those who skipped breakfast (19.33 ± 3.27kg/m2) was significantly higher than the BMI of those who ate breakfast (18.56 ± 3.05 kg/m2) (p=0.019). Most of the adolescents who ate a daily breakfast had mothers who had completed only primary school education although the relationship was not statistically significant (χ2 =5, p=0.172). Conclusion and Global Health Implications: Breakfast knowledge was low, while breakfast consumption was average. Adolescents who skipped breakfast had a significantly higher BMI (19.33 ± 3.27kg/m2) than those who ate breakfast (18.56 ± 3.05 kg/m2) (p=0.019). Nutrition education that emphasizes the importance of breakfast consumption with the purpose of behavioral change should be intensified among adolescents.