Medicinal plants, due to their potential therapeutic properties, have been employed in the national healthcare systems of various countries, including Vietnam. In Vietnam, at least 1,863 plant species have been officially used. However, limited information is reported on the standardizations of these plant extracts in the most up-to-date Vietnamese Pharmacopoeia 5.0, which only covers 19 monographs of plant extracts. Thus, this work presents the standardization of the ethanolic extract of the crab claw [“Càng cua” in Vietnamese] Peperomia pellucida (L.) Kunth, Piperaceae family, a wild-growing short-day vegetable plant commonly found in the South of Vietnam. The research described all the required characteristics of the Peperomia pellucida extract, their experimental processes, and the proposed acceptable criteria. These parameters included appearances, identification (apiol, thin layer chromatography, Rf = 0.214), loss on drying (6.38 ± 0.04%), total ash (23.9 ± 0.5%), heavy metals (≤ 20 ppm), microbial limits, and assay (total phenolic content of 677.97 ± 0.17 μg gallic acid equivalent/g powder). The complete standard data could be considered to be incorporated into the Vietnamese Pharmacopoeia in the future.