Background: Nurses are well-positioned to lead climate action efforts. There are several tools currently available for measuring nurses' awareness, attitudes and practices regarding climate change. While each of these existing tools provides valuable insights into nurses' awareness, attitudes, and practices regarding climate change, none of them address preparedness in taking actions in the near future, which is important to inform strategies for motivating climate change actions targeting nurses. Objectives: To describe the development and validation an instrument, provides a means to measure nurses internationally regarding their self-perceived engagement (achievement and preparedness), as well as their awareness and attitudes towards climate change. Methods: A self-administered structured questionnaire for a cross-sectional multinational survey was developed. The 2018 International Council of Nursing (ICN)'s Position Statement on Nurses, Climate Change and Health was used to guide the achievement and preparedness of climate change actions. An expert panel of six nursing scholars rated the content validity. Scale-level and item-level Content Validity Index (S-CVI and I-CVI) were calculated. Based on the first 509 responses from the survey, internal consistency was assessed by Cronbach's alpha, convergent validity by correlation analyses, and structural validity was assessed by exploratory factor analysis. Findings: The I-CVI of the final version was above 0.83 for all items except one. The S-CVI was 0.96. The internal consistency assessed by Cronbach's alpha was 0.943. All constructs were significantly positively associated with each other. Eight factors were identified by exploratory factor analysis, which structurally largely agree with the different parts of the questionnaire. Conclusion: The instrument is valid and reliable for assessing nurses' preparedness for climate change.