One of the learning media with mobile technology that can be used for education is 'smartphone.' This study developed a smartphone-based learning media capable of supporting physics learning on Microscope topics for XI grade high school students with a specialization in Mathematics and Natural Sciences (MIPA). This development product is in the form of teaching materials that can be accessed through an application on a smartphone. This learning media is validated by media experts and content experts. The development model used is modified Borg & Gall with seven stages, namely the preliminary research stage and information gathering, the planning stage, the preliminary product development stage, the design validation, the main product revision, the main field testing, and the operational product revision stage. The data obtained were analysed using equations and interpreted in the interpretation of the validation results assessment score. This development results reveal the validity value of smartphone-based learning media by content experts and media experts. The validity of media expert's states that it is valid for product development and the validity of material expert's states that the content developed in learning media is very valid. The accumulated student response to the application of smartphonebased learning media is very good.