Lightweight mortar is a specific type of mortar that is made by adding a foaming agent. A lightweight mortar has a lot of pores or cavities filled with air, which reduces the mortar’s weight. The lightweight mortar has better heat insulation than an ordinary mortar with its high porosity. There has been much research and application of lightweight mortar in the last few years. This review focuses on lightweight mortar made with a natural additive that has good high-temperature resistance. Many additives can be used, such as yeast and palm sugar. Yeast is a microorganism that can be used as a foaming agent because it can produce carbon dioxide (CO2) that creates a lot of pores in the mortar through the glycolysis process. Palm sugar is a disaccharide groups sugar, and sucrose, consisting of glucose and fructose. Glucose can reduce gypsum consumption in mortar and ettringite formation. Besides, sugar contains lignin, which can increase the bonding strength of mortar components. This study proves that the innovation of lightweight mortar with organic additives has a long-term potency with its durability at high temperatures.