The World Health Organization (WHO) Atlas-ID project was designed to collect, compile, and disseminate information on intellectual disabilities (ID) services and resources from across the world. This paper aims at selecting findings in the Atlas-ID that can be used as a tool for advocacy, human rights awareness, development planning, and monitoring changes regarding resources for persons with intellectual disabilities and their families in countries with the lowest levels of income in the world. After consultation with experts in the field of ID, a questionnaire and its accompanying glossary were developed. This questionnaire was completed by national respondents from 147 countries, areas, and territories that are WHO members (response rate of 74.6% corresponding to 94.6% of the world population). Cross-tabulations were calculated according to WHO region that the countries belong to as well as their levels of income. The data from the Atlas-ID allowed for documenting similarities and differences among the poorest and the richest countries of the world in relation to ID. The most striking differences pertain to the areas of information, judicial protection, government benefits, financing, availability, and access to services. The Atlas-ID allowed the identification of similarities and differences in resources and services between the four World Bank categories of countries income, and it demonstrated the extent of unmet needs in low-income and low-middle-income countries, as well as some critical gaps between these countries and the high-level income countries.