This study explores the economic feasibility and long-term potential of rooftop photovoltaic (PV) systems in multi-apartment buildings across the Baltic States (Latvia, Lithuania, and Estonia) through 2050. Using stochastic modeling and Monte Carlo simulations, it uniquely evaluates the Levelized Cost of Electricity (LCOE) for this sector, addressing uncertainties in economic, technical, and policy factors. The results show that rooftop PV systems are economically viable, with median LCOE values of 0.08 EUR/kWh for Latvia and Lithuania and 0.09 EUR/kWh for Estonia at a 6 % discount rate. Capital expenditures (CAPEX) are the most critical factor, with projected significant cost reductions by 2050 further enhancing viability. The region's rooftop solar potential, estimated at 40 GW, could attract over 150 billion euros in investments by 2050. Government incentives like subsidies, net metering, and EU funding have driven adoption, with installed capacities exceeding projections in recent years. However, gaps in collective self-consumption frameworks and energy community policies persist. For instance, Lithuania's "virtual net billing" model has boosted adoption, yet energy community initiatives remain underdeveloped. The study highlights rooftop PV systems' critical role in achieving EU energy goals, reducing reliance on fossil fuels, and enhancing energy security as the Baltic States integrate into the European electricity grid in 2025. Aligning policies, fostering community-driven models, and improving regulatory frameworks are essential for maximizing solar energy's contribution to sustainable energy transitions, in line with EU directives and UN Sustainable Development Goals (SDG-7).