The main purpose of this study was to innovate and assemble a Modular On-Grid Off-Grid Solar Energy System Mock-Up. Specifically, the study was conducted to provide student a simulation on solar setup particularly in Modular On-Grid Off-Grid Solar Energy System Mock-Up in order to prepare them in the actual field. The study was conducted at Bohol Island State University – Main Campus in the School Year 2021-2022. The researcher used experimental method of research in developing the gadget. There are four (4) experts as the respondents of this study. All of them are the electrical technology instructors from BISU main campus who witness and test the level of performance and effectiveness using On-Grid Off-Grid solar energy system Mock-up. The Modular On-Grid Off-Grid solar energy Mock-Up composed by Solar panel, Maximum power point tracking (MPPT), On-Grid inverter, Off-Grid inverter, Automatic transfer switch (ATS), Alternating current power monitor, Battery Management System (BMS), Batteries, Bulb and Switches. The researcher made an observation guide and conducted a trial and error to obtain necessary information to oversee the functionality of the device in terms of performance and effectiveness. The data collected on the performance of the Modular On-Grid Off-Grid Solar Energy System Mock-Up was analyzed and interpreted. The researcher concluded that Modular On-Grid Off-Grid Solar Energy System Mock-Up was found functional and very usefull that can be used by the students, instructors, and future researcher as an instructional apparatus. The researcher recommended and encouraged students of Electrical Technology to use the Modular On-Grid Off-Grid Solar Energy System Mock-Up as their instructional apparatus.