The environmental impact produced by digital technologies is one of the fundamental contents to be developed by teachers of the 21st century. Different investigations raise the need to redesign education towards sustainable models and promote a critical look at digital technologies. The main objective of this manuscript is to design a valid, reliable and useful scale to measure self-perceived teacher digital competence regarding the eco-responsible use of technologies. The instrument has been designed based on a detailed analysis of the main frameworks for the development of digital competence in Europe: INTEF and DigCompEdu. A content validation process has been followed through the expert judgment method. Subsequently, its reliability and validity are estimated using structural equation modeling techniques. The results obtained guarantee the reliability and validity of the model. Therefore, the need to establish environmental teacher training plans and more awareness about the eco-responsible use of technologies is established.