Determining the candidate teachers' opinions regarding self-efficacy towards alternative assessment will be beneficial in that this will improve their competencies while using these approaches in their applications within the classroom. In this article, the development and validation of the "Self-efficacy towards Using Alternative Assessment Scale" (SUAAS) is introduced. The SUUAS is a 26-item scale for assessing candidate teachers' self-efficacy towards using alternative assessment. Data collected from 424 candidate teachers provide evidence for the validity and reliability of the scale. The results provide evidence for a valid and reliable self-efficacy scale with 3 factors, which are named as 'Self-efficacy towards Using", "Self-efficacy towards Challenges" and "Self-efficacy towards Using Sources". The Cronbach's alpha value of the entire scale has been found as 0.89, while those of the sub-factors are 0.88, 0.86 and 0.71, respectively. Followed by additional validation studies, the SUAAS will serve as a valuable tool for both instructors and researchers in education to assess teachers' and candidate teachers' beliefs related to their self-efficacy towards using alternative assessment approaches.