Introduction The curriculum for Norwegian students has recently been changed to include the interdisciplinary subject “Health and life skills”. The main aim of this topic is to give the pupils competence to promote health and mastery, and to provide them with better skills for making responsible life choices. However, it is unknown what effects such curricular changes has for the children’s mental health. The objective of the present study is to conduct a systematic literature review to understand whether countries AND/OR areas with a population of one million people or more have evaluated consequences for mental health due to changes in curriculum for students in primary school AND/OR secondary school/college AND/OR sixth form/high school. A secondary purpose is to evaluate the effect sizes of such curriculum changes on the children’s mental health, e.g., through meta-analysis if there is sufficient number (n ≥ 5) of studies. Methods The review will follow the PRISMA statement, with the present protocol reported according to PRISMA for systematic review protocols (PRISMA-P). Eligibility criteria The eligibility criteria are described below. Criteria Description 1. Language: Is written in English, French, German, Italian, Portuguese, Spanish, Norwegian, Danish or Swedish language 2. (Any) Effect: Includes measure of any effect, including retrospective 3. Mental Health Outcome: Includes measure of mental health outcome 4. Curricular change: Evaluates change(s) to curriculum 5. School: Study is conducted in Primary Schools AND/OR Secondary Schools AND/OR sixth forms 6. Designated Area: Study is conducted within a designated area 7. Article format: Exclude conference abstracts or single case study formats Note. A “designated area” is in this context defined as a country of any size, or an area with 1 million residents or more, such as a larger city or state. Also, a single case study format is when only the perspective of one person is included, even if it is the perspective about something that is relevant to multiple people. Articles from any year will be included. Search Strategy: The PhD Fellow (Siri Hausland Folstad) started the pilot search for articles in English language in relevant databases in August. Databases included are Embase Classic + Embase, ERIC, Global Health, PubMed, APA PsycInfo, Scopus, CINAHL, but more databases specific for other languages than English mays be added. For articles in Scandinavian language (Norwegian, Danish and Swedish) and in French, German, Italian, Portuguese and Spanish language, separate searches will be conducted with keywords in the aforementioned languages. We have combined search terms synonymous or related to ‘child’, ‘mental health’, ‘curriculum’ and ‘school’. Please see our ‘search words’ document attached for the English language keywords. In every search Miss Folstad has looked at the title and abstract of the first 20 articles to get an impression of whether the search seems to capture relevant articles. For the searches in the aforementioned languages, the English keywords will either be translated directly or to meaningful equivalents. Since the beginning of the pilot search, Miss Folstad has collaborated with the project team to expand the search to include a greater variety of mental health words, such as positive psychology words (e.g. happy, happiness and flourishing). Additionally, the word ‘college’ has been added to the school words as this is commonly used for sixth form in the UK. Prior to the screening process, clear eligibility criteria have been defined. The screening process of studies in English and Scandinavian language will be conducted in the program Covidence (covidence.org). Studies in English language will be screened first, whilst those in Scandinavian language will be added at a later stage. Firstly, two Research Assistants will screen the identified article titles and abstracts. After the first 300 and second 300 articles, the Research Assistant will meet with Miss Folstad to discuss the process and any uncertainties they may have been experiencing. Throughout the screening process, any disagreements will be resolved by consulting Miss Folstad. Secondly, Miss Folstad will together with a second PhD Fellow (Ingvild Røsand) do the full text screening. The ratio of disagreement in the different stages of the process will be calculated in Covidence and displayed in the article. Articles in English and the Scandinavian languages will be screened by two people. Articles in the remaining languages, i.e., in French, German, Italian, Portuguese and Spanish, will only be screened by the Research Assistant, Patricia Magalhaes, as she is the only one who speaks these languages. The articles screened in this way will be clearly separated in the write-up of the review from those identified based on the PRISMA guidelines protocol.