In Tibetan Buddhism, Vajrakilaya (Sanskrit: वज्रकीलाय, romanized: Vajrakīlāya, lit. 'Diamond-dagger', also वज्रकील, Vajrakīla; Tibetan: རྡོ་རྗེ་ཕུར་པ, Wylie: rdo rje phur pa, THL: Dorje Phurba or Vajrakumara (Sanskrit: वज्रकुमार, romanized: Vajrakumāra, lit. 'Diamond-youth'; Tibetan: རྡོ་རྗེ་གཞོན་ནུ, Wylie: rdo rje gzhon nu, THL: Dorje Shönnu) is a wrathful heruka yidam deity who embodies the enlightened activity of all the Buddhas. His practice is known for being the most powerful for removing obstacles and destroying the forces hostile to compassion. Vajrakilaya is one of the eight deities of Kagyé.^{[citation needed]}

Vajrakilaya is a wrathful form of the Buddha Vajrasattva. His distinctive iconographic trait is that he holds the dagger called phurba or kīla. Vajrakilaya is commonly represented with three faces of different colors in a crown of skulls. The central face is blue, the left is red and the right is white. He also has six arms: two hold the phurba, two hold one vajra each, one holds a flaming snare, and one a trident. He crushes under his feet demons representing the obstacles to spiritual realization.

Vajrakilaya is a significant Vajrayana deity who transmutes and transcends obstacles and obscurations. Padmasambhava achieved realisation through practicing Yangdag Heruka (Tibetan: yang dag he ru ka), but only after combining it with the practice of Vajrakilaya to clean and clear obstacles and obscurations.

Vajrakilaya is also understood as the embodiment of activities of the Buddha mind. According to Dilgo Khyentse Rinpoche, Vajrakilaya is perceived as the wrathful form of Vajrapani. Many great masters both in India and Tibet, but especially in Tibet, have practiced Vajrakilaya (especially in the Nyingma lineage, and among the Kagyu and also within the Sakya). The Sakya's main deity, besides Hevajra, is Vajrakilaya.^{[citation needed]}

Jamyang Khyentse Wangpo, Dilgo Khyentse Rinpoche, Dudjom Rinpoche and a significant number of lamas within the Kagyu and Nyingma engaged Vajrakilaya sadhana.^{[citation needed]}

A common manifestation of Vajrakilaya has three heads, six arms, and four legs. Vajrakilaya's three right hands except for the right front one held vajras with five and nine prongs. The right front one makes a mudra as granting boons with open palm. Vajrakilaya's three left hands hold a flaming triple wishfulfilling jewel or triratna, a trident and the phurba. Vajrakilaya's back is covered by the freshly flayed skin of the elephant representing 'ignorance' (Sanskrit: avidya; Tibetan: marigpa), with the legs tied in front. A human skin is tied diagonally across his chest with the hands lying flat on Vajrakilaya's stomach and solar plexus.

A rope ripples over his body with severed heads hanging by their hair representing the Akshamala or 'garland of bija' (Sanskrit: Varnamala). A knee length loin cloth winds around his belly belted with a tiger skin complete with tail, claws and head. This deity wears manifold nāga adornments and jewellery: naga earrings, naga bracelets, naga anklets and a naga cord over his chest, sometimes referred to as a naga girdle and a naga hairpiece or hair ornament.

Vajrakilaya is the deity of the magic thunderbolt, the phurba, a tool of the sharp adamantine point of Dharmakaya, a wisdom forced through the power of one-pointed concentration. This 'one-pointed' (Sanskrit: eka graha) focus is a concerted mindfulness on the unity and interdependence of all dharmas. This one-pointed focus is understood as 'applying oneself fully' (Tibetan: sgrim pa). The three pointed blade represents delusion, attachment and aversion transformation.