Teacher shortage is reported to be a challenge worldwide. In a recent report,United Nations Educational, Scientific and Cultural Organization (UNESCO) reported the need for some 44 million new teachers in schools to reach the Agenda 2030 targets. Attracting, recruiting and retaining new teachers is difficult in relation to both geographical areas and in certain subjects, being a common challenge of many developed countries and is seen in many countries of the world. Teacher shortage and the lack of teachers has consequences as teaching in schools, students’ learning and therefore the quality of education is affected. The aim of this paper was to study teacher shortage in schools through a literature review in order to explore the causes of the teacher shortage described in current literature and understand these causes based on teacher attrition, teacher recruitment and teacher retention. The included articles of this literature review were peer-reviewed articles regarding teacher shortage from 2018-2023 which were identified using the Scopus database. Some 52 of articles met the inclusion criteria of this literature review. The articles represented 18 different countries all over the world. The chosen methods of the studies also varied, for example, qualitative and quantitative studies. The content of the included articles was thematically encoded and categorized by the described a)reasons behind, b) area/subject c) and discussed solutions. The themes were identified inductively; they were strongly linked to the data, and the steps of qualitative content analysis were followed to identify these themes. The overall conclusion is that teacher shortage is multifaceted and complex. There are many reasons behind teacher shortage and there are many aspects that interact on several different levels. In order to alleviate teacher attrition and promote teacher recruitment and retention, collective initiatives by many of the stakeholders involved will be necessary.