Aims: The objective was to investigate if gender differences exist in the associations between periodontitis and type 2 diabetes. Disproportionate disparities by gender were found to exist in rates of both periodontitis and diabetes with respect to demographics and behavioural predictors that cannot be explained solely by the well-established association between these two diseases. Materials and methods: Multiple datasets were extracted from the National Health and Nutrition Examination Survey (NHANES) 2009–2014, which used a stratified multistage probability sampling to obtain samples from all civilian non-institutionalised people in the USA. Bivariate relationships between each explanatory variable and periodontitis level were assessed with odds ratios (OR) and their 95% confidence intervals (CI). A set of weighted logistic regression models was used to investigate the association differentiations between periodontitis and diabetes by gender. C-statistics measured the goodness-of-fit of weighted logistic regression models. Results: The prevalence of moderate–severe periodontitis was 36.39% and 22.71% among participants with type 2 diabetes and without diabetes, respectively. Type 2 diabetes was significantly associated with moderate–severe periodontitis OR (OR = 1.47, 95% CI: 1.18–1.82) among males even after adjusting for demographics, socioeconomic status and oral health behaviours. The aforementioned relationship was not found in females. Furthermore, different relationships of moderate–severe periodontitis with body mass index and the use of mouthwash were found between the males and females. Conclusions: The current findings suggest that important improvements in the development of gender-specific strategies in prevention, such as oral home-care, to reduce the high prevalence of periodontal disease and maintain good oral health are vital, and are especially important for male diabetic patients and those who are at high risk of developing diabetes, such as those who are obese.