Self-regulated learning (SRL) involves processes by which learners purposefully direct their cognitions, emotions, and behaviors towards the achievement of personal learning goals. Research has shown that young learners often struggle with SRL. Educational technology could be useful to support their SRL. However, it remains unclear how support mechanisms can be best adapted to the needs of children. Adopting a participatory design (PD) approach involving an intergenerational design team of six children (ages 10-12) and three adult facilitators, we explored children's perspectives on factors that facilitate or hinder their SRL, and what kinds of support they desire. The study consisted of three in-person co-design sessions (one per week) lasting about 90 min each over three weeks. The sessions centered on brainstorming needs, evaluating existing technology, ideating and designing paper prototypes of study-planner apps. Our findings indicate that children primarily voice the need for support to better organize their study and to keep focused on the learning task at hand. They also make it clear that SRL support systems must be designed to be attractive and fun. Children's subsequent evaluation of app features and the prototypes which they designed were consistent with these needs. Taken together, our study indicates that children can voice clear and consistent preferences for SRL support with educational technology. By including children in the design process, we can ensure that educational technologies effectively meet their needs, enhance their learning experiences, and promote self-regulation and academic success.