To better investigate why positive behaviour and misbehaviour occur, the study aimed to examine the relationships among teachers’ autonomy support and students’ advantageous comparison, non-responsibility, positive behaviour, and misbehaviour. We also examined the mediating roles of advantageous comparison and non-responsibility in these relations. The participants were 478 students with an average age of 14.6 ± 1.49 years, and the students included 259 males and 219 females. Structural equation modelling indicated that teachers’ autonomy support had direct negative effects on advantageous comparison and non-responsibility. Furthermore, advantageous comparison and non-responsibility had direct positive effects on students’ misbehaviour and had direct negative effects on positive behaviour. The relationships between teachers’ autonomy support and students’ misbehaviour and positive behaviour were mediated by advantageous comparison and non-responsibility. In line with previous work, teacher autonomy support might be critical to enhancing students’ positive behaviour as well as reducing their misbehaviour. Since the mediating roles of advantageous comparison and non-responsibility were confirmed, we also suggest that strategies should be applied to eliminate students’ moral disengagement.

为了更好地调查积极行为和不当行为发生的原因，该研究旨在检验教师自主支持与学生有利比较，无责任，积极行为和不当行为之间的关系。我们还研究了在这些关系中有利的比较和不负责任的中介作用。参与者为478名学生，平均年龄为14.6±1.49岁，其中包括259位男性和219位女性。结构方程模型表明，教师的自主支持对有利的比较和不负责任产生直接的负面影响。此外，有利的比较和不负责任对学生的不良行为具有直接的积极影响，而对积极行为具有直接的不利影响。教师的自主支持与学生的不当行为和积极行为之间的关系是通过有利的比较和不负责任的关系来实现的。与以前的工作一致，教师自治支持对于增强学生的积极行为并减少其不良行为可能至关重要。由于确定了有利的比较和非责任的中介作用，我们还建议应采取策略消除学生的道德失范。