The purpose of this study was to develop a valid and reliable "Environmental Attitude Scale" (EAS) for secondary school (5th, 8th grade), high school (11th) and undergraduate college students. The reliability and validity studies of the scale were carried out in three different countries (Finland, USA and Turkey). The sampling size was 1687 students. For the construct validity, exploratory factor analysis (EFA) was run and in order to test the accuracy of the obtained factor structure. The scale was composed of three sub scales: "Environmental Behaviour Sub Scale (EBSS)", "Environmental Opinion Sub Scale (EOSS)" and "Environmental Emotion Sub Scale (EESS)". The EBSS and EESS consist of two factors each and the EOSS consists of one factor. The EBSS had 13 items, EOSS 11 items and EESS 16 items, all using a 5- point Likert scale. The Cronbach alpha reliability coefficient for the whole scale was found to be a=.94, and reliability coefficient of the first subscale was found to be a=0.91, second subscale a=.82 and third subscale a=0.94 and the Spearman Brown coefficients were found to be .85, .83, .80 and .85, respectively. Reliability and validity results of the study show that the "Environmental Attitude Scale" can be used to measure the environmental attitudes of the different levels of students.