Proteins can be an excellent byproduct of the biorefining of lignocellulosic materials. In this work, extraction conditions for the white leaf proteins (cytoplasmic) of ammonia-treated dwarf elephant grass were established to obtain a protein juice suitable for the production of leaf protein concentrates. A calcium hydroxide solution was used as extracting agent, at several solid-liquid ratios, pHs, temperatures, and times. Extractions were carried out in Erlenmeyer flasks containing 5 g (dry basis) of forage with constant agitation (100 rpm). The soluble protein content was determined by the Lowry method. Optimal extraction conditions for the ammonia-treated forage were 12.60 pH, 1:10 solid-liquid ratio, 90 degrees C, and 30 min extraction time, resulting in 52.65% extraction yield. The ammonia treatment significantly increased (p < 0.05) the release of proteins from the fibrous matrix, facilitating their extraction.