One of the key conditions for ensuring quality teaching is happy and satisfied teachers in schools. Th is study aimed to conceptualize the basic principles of happiness and to adapt international tools for use by teachers in the Czech environment with which the construct can be reliably measured. Th e subjective level of happiness in this study was determined through a sample of 604 primary school teachers. An abbreviated eight-item version of the Oxford Happiness Questionnaire and the four-item Subjective Happiness Scale were administered to the respondents in early 2020 (before the school closures resulting from the SARS-CoV-2 pandemic situation). Th e results of the psychometric analyses confirmed the expected one-factor structure, criterion validity, and high internal consistency of both the instruments that were tested. A multigroup confirmatory factor analysis also showed that in the Czech versions of both questionnaires a full strict invariance of measurements was achieved for the groups of teachers that were tested in terms of the school level at which they declared that they were teaching. It turned out that the primary school teachers achieved relatively high scores on both the scales that were tested, with only a slightly higher degree of happiness declared by the lower primary school teachers as compared to their colleagues teaching in the upper primary school. The limits of the study and directions for future research are discussed, as are further uses of the tools that were tested, which can be recommended both for research purposes and for the purposes of pedagogic diagnostics in practice.