'Moonlight', Chinese: 月光菩薩; pinyin: Yuèguāng Púsà; Rōmaji: Gakkō or Gekkō Bosatsu) is a bodhisattva often seen with Sūryaprabha, as the two siblings serve Bhaiṣajyaguru.

[2] Within the Vajra Dhātu Mandala (金刚界), Moonlight Bodhisattva resides in the western portion of the Second Court of the Micro Assembly.

In this mandala, Moonlight Bodhisattva's secret name is Vajra-tejas, and their Samaya symbol is a blue lotus flower with a half-moon placed atop it.

"[4] The Record of Awakening and Zen quotes from Volume 1 of the Commentary on the Scripture of the Medicine Buddha (药师经疏): In the past world, during the time of Dipankara, a Brahman (a Hindu priest or ascetic) and his two sons made a shared Bodhisattva vow to alleviate the suffering of all sentient beings.

[4][5] According to the Ritual for Arranging the Altar in the Medicine Buddha Practice (修药师仪轨布坛法), Moonlight Bodhisattva is depicted with a white body, seated on a goose throne, and holding a moon wheel.

Another interpretation suggests that Medicine Master Buddha of the Eastern Pure Land and Sunlight and Moonlight Bodhisattvas are in a parent-child relationship.

The mantra of Moonlight Bodhisattva goes: "Namo Ratnasuhaaya, Arahata, Mitra Uddhaaya, Sankhadhaaraaya, Avalokitava, Jvalodhaaraaya, Kshitigarbhaaya, Sarva Sattva Hridayaya.