This cross-sectional study examined parents’ attitudes, their support, and perceptions of school involvement in school sports using a newly developed Parental Attitudes and Support for School Sports and Perceptions of School Involvement Questionnaire (PASSIQ). The study also examined the association between parents' gender and children's sports participation concerning these attitudes and support levels. A total of 380 parents were included in the study, with 341 valid responses analyzed. Our findings indicate that higher levels of parental support are strongly associated with more positive attitudes toward school sports (p < 0.001). While perceptions of school support showed a marginally significant positive relationship (p = 0.083), extended participation in sports was generally associated with lower parental attitudes, potentially reflecting concerns about burnout or shifting perceptions over time. Notably, the interaction between parents' gender and children's sports participation revealed that for male parents, extended sports participation of their children significantly enhanced positive attitudes toward school sports (p = 0.004). These results highlight the importance of considering parental support and gender-specific responses when developing strategies to promote positive attitudes and support for school sports. The PASSIQ proved to be a reliable and valid tool for assessing these constructs, providing a foundation for future research and interventions to foster supportive environments for children's physical activity.