Higher education institutions consider student satisfaction to be one of the main factors in determining the quality of their online learning. The purpose of this study was to develop a reliable, valid, and practical instrument to measure online students' satisfaction as well as to explore the psychometric and theoretical concerns surrounding the construct validity of existing satisfaction scales. The study was carried out in 2017-2018 fall and spring with participants consisting of freshmen who took the online course in a state university (N-fall=1585; N-spring=1206). In this study exploratory factor analysis (EFA) (Study 1-N-EFA=921) and confirmatory factor analysis (CFA) (Study 1-N-CFA=664; Study 1-N-CFA=1206) were performed to assess the construct validity of the scale's measures. As proof of validity, the effect of gender on satisfaction was examined, for which independent sample t-test was performed. For the criterion validity, the relationship between computer and internet self-efficacy and satisfaction scores of the learners was examined. The finalized version of satisfaction scale, consisting of eight items, demonstrated that the scale is suitable for general use. Suggestions for future researchers and practioners are proposed.