Generally, tax morale is defined as an umbrella capturing non-financial incentives for tax compliance and factors outside the standard and expected framework. Therefore, this paper prioritizes the factors affecting tax morale. This is mixed-method research. The mixed method is a procedure for collecting and analyzing quantitative and qualitative data in a study or a set of studies based on sequential and concurrent information. This paper first adopts the qualitative approach, followed by the quantitative approach. The Grounded theory approach is used to solve the research problem in the qualitative stage. This article adopted Strauss and Corbin's method and finally presented tax morale in six components, including causal, intervening, contextual, phenomenal, strategy and results of tax morale. This article prioritized the components identified from the Grounded Theory with two approaches, namely DEMATEL and ANP, and the sub-criteria were determined by 15 experts who had lived experience in taxation. The results showed that among the identified factors, the phenomenal category in the tax morale was the most significant, with a weight of $41\%$; followed by strategy and results, the causal category; and finally, the intervening and contextual categories are ranked next. The study results can be a guide for receiving taxes, and considering the identified components is a big step towards advancing tax goals and paving the path to achieving the taxation goals.