Introduction: There is strong evidence that people with disabilities suffer from a significant digital divide. However, there are reports indicating that Internet use may result in many benefits for those with disabilities. The aim of the study was to assess the impact that the use of the Internet has on the wellbeing and health behaviours of persons with disabilities. Methods: An analysis was carried out using the dataset obtained from Social Diagnosis, a panel study undertaken on a nationally representative sample. The records of persons with disabilities were retrieved from the dataset which was established in 2015. An analysis of the association between Internet use and the wellbeing, mental health and health behaviours of the respondents was undertaken. The variables reflecting the self-assessment of their own life and experience of loneliness were treated as being indicators of their wellbeing and the prevalence of suicidal thoughts or making use of psychological help as indicators of mental health. The health behaviours analysed in the study included smoking, excessive consumption of alcohol and undertaking physical activity. For all these variables, multivariate logistic regression models were developed. The effect of Internet use was adjusted for sociodemographic variables and the degree of disability. An analysis was performed after applying post-stratification weights available from the Social Diagnosis study. Results: The weighted study group consisted of 2529 people having a mean age of 59.33 ± 16.89 years. The group included 20.71% (N = 524) respondents with a mild, 41.58% (N = 1052) with a moderate, and 26.54% (N = 671) with a severe disability. The proportion of Internet users was 37.07% (N = 937). In all the regression models, Internet use had a significant impact on the dependent variables. After adjustment for sociodemographic variables and the degree of disability, the Internet users more frequently assessed their lives as happy (odds ratio, 95% confidence interval: 1.86, 1.47–2.37) and less frequently experienced loneliness (0.63, 0.49–0.81) or suicidal thoughts (0.47, 0.35–0.65). In addition, they needed psychological help less frequently (0.50, 0.35–0.72). Interestingly, Internet users undertook some form of physical activity or sport more often (2.41, 1.87–3.13) and fewer smoked cigarettes (0.70, 0.54–0.91) or consumed alcohol excessively (0.32, 0.19–0.56). Conclusions: The use of the Internet by people with disabilities was associated with improved wellbeing, better mental health and more beneficial health behaviours. These findings support the development of intensive actions to reduce the digital divide for the population of people with disabilities.