Background: Teacher Participation in decision-making is one of the recommendations of school-based management and one of the key characteristics of an effective school. Although teacher participation in decision making is claimed to be correlated with their affective outcome, few researchers have been attempted to verify the predictive effectiveness of participation in different decision domains under a multi-dimensional participatory model on their affective outcomes. This study intends to identify an empirical participatory model ought to help school administrators involve teachers in appropriate decisions for improving teachers' affective outcomes, which result in quality decision-making. Aims: To examine theoretically the causal relationship between teacher participation in decision-making and their affective outcome for developing a participatory decision model, and identify the decision domains that would assist school administrators to effectively involve teachers in decision-making under the school-based management policy. Sample: Questionnaires were sent to 20 secondary schools in Hong Kong. A total of 335 teacher-completed questionnaires were collected from all the target schools. Methods: Theoretical model and questionnaires were constructed by synthesizing theories from literatures, principal axis factor analysis and reliability test were used to validate the constructed validity and reliability of the questionnaires. Structural equation modeling was applied to validate the participatory model and estimate the correlation among the variables. Results: The results showed that a multi-dimensional decision was identified by the structural equation modeling, the relationship among the variables of the model were also explored. The three dimensional decision model includes instructional, curriculum and managerial domains; and the variables of the affective outcome include job satisfaction, job commitment and perception of workload. All the affective outcomes were related to the form and extent of teachers' participation in decision-making. Conclusion: This study extends our knowledge of the relationships between decision-making involvement and affective outcomes. It does not support the theory that a school-based management governance structure automatically enhances teachers' participation in decision-making. School administrators should encourage teacher participation in curriculum and managerial decision domains, as the intent of the ABM policy is to increase job satisfaction and to enhance greater commitment to the school policies. (Contains 3 figures and 1 table.)