The main purpose of this study was to explore the relationships between pupils¡¦ multiple intelligences, action control, self-regulation, demographic variables, and their competences of everyday problem solving. The participants were 453 fifth and sixth graders (238 boys and 215 girls) sampling from elementary schools in Kaohsiung City. The employed instruments included The Multiple Intelligences Appraisal, The Action Control Scale (ACS), The Self-regulated Learning Strategies Inventory, and The Everyday Problem-Solving Test (EPST). The applied analysis methods were Descriptive Statistics, One-way Multivariate Analysis of Variance, One-way Analysis of Variance, Canonical Correlation Analysis, and Discriminant Analysis. The main findings of this study were as follows: 1.The participants were not very competent in everyday problem solving. Among the four indices of everyday problem solving, the participants had comparably better abilities in ¡§defining multiple problems¡¨ and ¡§setting priority¡¨ than those in ¡§proposing solutions¡¨ and ¡§deciding the best solution¡¨. 2.The participants¡¦ development of multiple intelligences and their abilities in action control as well as self-regulation were in above-average level. 3.The pupils who had higher multiple intelligences outperformed their counterparts in everyday problem solving; moreover, the pupils¡¦ logical-mathematical intelligence was strongly correlated with their problem solving abilities of ¡§proposing solutions¡¨ and ¡§deciding the best solution¡¨. 4.Pupils with the action-oriented style of action control outperformed those with the state-oriented style in everyday problem solving; in addition, the pupils¡¦ abilities in dealing with ¡¨non-preoccupation with failure¡¨ and ¡§non-hesitation with decision¡¨ were positively correlated with their problem solving ability of ¡§proposing solutions¡¨. 5.The pupils who had more mechanism of self-regulation outperformed their counterparts in everyday problem solving; besides, the pupils¡¦ ¡§self-evaluating and confidence¡¨ in self-regulation was highly correlated with their problem solving ability of ¡§proposing solutions¡¨. 6.The sixth graders¡¦ overall competence in everyday problem solving was better than that of the fifth graders. Moreover, the sixth graders outperformed the fifth graders on the abilities of ¡§setting priority¡¨, ¡§proposing solutions¡¨, and ¡§deciding the best solution¡¨. 7.There were no significant gender differences on the pupils¡¦ overall performance in everyday problem solving, nor on the four indices of everyday problem solving. 8.Birth order had significant effects on the pupils¡¦ performance of everyday problem solving. More specifically, those first-born pupils (including the only child and the first born children) outperformed the middle-born pupils in ¡§defining multiple problems¡¨ and ¡§proposing solutions¡¨. 9.The pupils¡¦ multiple intelligences, action control, self-regulation, and demographic variables could jointly predict their ability group of everyday problem solving, among the three levels of ability group, the ¡§high ability¡¨ group could be best predicted. Finally, after discussion, some suggestions were proposed for educational institutions, teachers, parents and future further studies.