Climate literacy is one of the key components of empowering citizens to face climate change, yet no standardized, internationally agreed instrument currently exists for assessing it, and researchers in different countries have relied on varying approaches to develop their own questionnaires. Using a systematic review based on the PRISMA framework, this article examines global experiences in developing climate literacy questionnaires to identify the theoretical frameworks, assessment dimensions and components, validation methods, and factors influencing climate literacy across different countries. A systematic search was conducted in Scopus, Web of Science, and Science Direct, as well as authoritative domestic sources, covering the period 2020–2026, using Persian and English keywords related to climate literacy. After screening based on inclusion and exclusion criteria, studies from Canada, Germany, Spain, Suriname, South Korea, England, Indonesia, and the United States, along with 2 credible studies from Iran, were included in the final analysis. Findings show that the most common theoretical framework is the Knowledge-Attitude-Behavior model and its developed versions, and more recent studies from Canada and Germany emphasize climate information processing, scientific skills, and source-credibility evaluation. In Iran, climate literacy levels are favorable among some student groups but low among school pupils and accompanied by incorrect scientific beliefs. The most important factors influencing climate literacy are education, media exposure, direct experience of climate hazards, trust in scientific sources, and psychological factors such as attitude and self-efficacy. Based on this review, a comprehensive conceptual framework is presented at four levels: 1) background and demographic factors, 2) core dimensions of climate literacy, 3) mediating variables and behavioral readiness, and 4) outcomes of climate literacy. This framework can serve as a basis for designing standardized climate literacy assessment questionnaires in Iran and related literacy-improvement programs.