The United Nations defined illiteracy as the condition of a person who can not read and write, and in 1971 issued another definition that states: "Every person who has acquired the necessary information and abilities to practice all activities in which the knowledge of the language is necessary to play his role effectively in his community, in addition to learning to read, write and calculate results that enable him to elevate himself and the group to which he belongs, and allows him to participate actively in the life of his country".

The illiteracy is a societal phenomenon with negative effects spread in many countries across the world. Its standards differ from one society to another depending on its technological superiority and the difference of time as well. In the primitive and simple societies, illiteracy was related to the literacy of the majority of developing countries and third world countries. The standards of illiteracy have multiplied and there are several skills considered to be illiteracy if we lost them , the most important being the ability to access and use data by different sources of knowledge or so-called information culture, which meant to develop a complex set of skills that allow individuals to test, experience and understand the flow of ideas through rapid changes in the technological environment.

Today, 17% of the world's adult population is illiterate. Two-thirds of the world's population is women. There are 122 million illiterate young adults in the world, 60.7% of whom are women. The number of children who are out of school and are a source of concern for the future is 67.4 million.
- Low level of education for parents.
- The existence of learning disabilities, such as dyslexia, difficulty and slow learning.
- The lack of laws and regulations that obligate schools to enroll in non-educated schools, in addition to the lack of seriousness in implementing these laws, if any.
- Some societies have been influenced by customs and traditions that prevent women from participating in public life, including exercising their right to education.
- The lack of justice in the distribution of public services in different areas of the country, and this often results in the access of urban people to better educational services compared to those living in the village.
- Effect of the efficiency of teachers who teach the first grades on the achievement of these students.
- Failure to take care of the rehabilitation of specialized teachers to educate the elderly.
- Political instability and ongoing wars and migrations in some countries.
- Children do not complete their education when they reach a certain educational stage and leave them to study for a variety of reasons, including the difficult social and economic conditions of the parents, forcing the child to leave school and join the labor market.
- The increasing number of people requiring more services, including education facilities, and in the event of a weak economic potential of the state, it will not be able to meet these needs.
- There is no correlation between the outputs of academic education and their employment in vocational education.
- Students evade classes.

Ways to reduce illiteracy
Governments and organizations devote considerable efforts and resources to combating and overcoming illiteracy,through :
- The preparation of specialized programs through which teachers are trained to acquire the necessary professional and educational skills.
- Eliminate customs and traditions that prevent access to education opportunities.
- Involvement of social bodies.
- Media is an important means of informing the community about the importance of education and the advantages and opportunities it entails.
- Re-design adult education curricula that suit their interests.
- Provide incentives for the learner.
- Work on the development of other types of non-formal education.