Indonesia, as a country with a large population and rapid economic growth, requires high quality infrastructure. Due to the increasing global population,, climate change, resource scarcity, and demand for more efficient, innovation in construction material technology become crucial. One such innovation is the use of geopolymer mortar, which is environmentally friendly because it does not involve the use of cement. This study aims to determine the effect of lime on geopolymer mortar with fly ash and rice husk ash in 12 Molar NaOH on compressive strength, setting time, and porosity of the mortar, and to identify the optimal lime ratio. The experimental method uses cube samples with dimensions 5x5x5 cm3. The lime ratios used are 1%, 2.5%, 5%, and 7.5%, while the fly ash ratio is 0.8% and the rice husk ash ratio is 0.2%. The results indicate that higher lime ratios result in lower the compressive strength, higher porosity percentages, and faster the initial and final setting times. The optimal lime ratio is 1%, with a compressive strength of 7,568 MPa and the lowest porosity percentage of 17,894% at 28 days of age.