The objective of this research is to develop indicators of happiness in science learning among upper secondary school students and to analyze the components of indicators of happiness in science learning among upper secondary school students. The sample group consisted of 960 upper secondary school students enrolled in the second semester of the 2022 academic year under the Nakhon Sawan Secondary Educational Service Area Office, selected using multistage random sampling. The research instrument was a questionnaire consisting of 48 items using a five-point Likert scale. Content validity was examined by five experts, and the reliability was analyzed using Cronbach's alpha coefficient and data were analyzed using exploratory factor analysis (EFA) with the SPSS. The research findings revealed that there were 48 indicators of happiness in science learning among upper secondary school students. The content validity ranged from 0.60 to 1.00, and the reliability coefficient was 0.98. The results of the exploratory factor analysis of the indicators of happiness in science learning among upper secondary school students revealed four components: (1) positive attitudes toward science learning, consisting of 13 indicators; (2) discipline in science learning, consisting of 15 indicators; (3) self-management for the development of science learning, consisting of 11 indicators; and (4) positive relationships in science learning, consisting of 9 indicators. Together, these four components accounted for 94.089% of the total variance.