During the COVID-19 pandemic, students have been forced to learn at home. Authentic contexts are essential to designing useful learning activities. Therefore, this study used mobile technology, namely Ubiquitous Geometry (UG), to merge authentic contexts into learning activities and investigate the influence of authentic contextual learning (ACL) on students’ and parents’ perceptions. This is because parents inevitably have an effect on students’ learning at home, which has not been clearly addressed in past studies. This study investigated students’ and parents’ perceptions in terms of technological and pedagogical aspects of the implementation of ACL supported by UG while learning at home. We conducted one experiment on 20 fifth-grade students and their parents. In the students’ acceptance model, the results indicated that students’ ease of use and usefulness significantly influenced their positive attitude toward ACL supported by UG, and the positive attitude also significantly influenced intention to continue using our proposed system in both the technological and pedagogical aspects. In the mutual influence between students’ and parents’ acceptance model, it was found that parents significantly influenced their children’s perceptions of ACL at home. In the mediation analysis, we found parents’ ease of use and intention to use could mediate the relation between students’ positive attitude and intention to use in the pedagogical aspect. From the interview, we found that parents thought that the learning activity in authentic contexts was useful and encouraged their children to do more engagement. However, in the technological aspect of the mutual influence between students’ and parents’ acceptance model, no mediation existed. This might be because parents worried their children were overusing mobile devices.