In Tibetan Buddhism, the path to Enlightenment is frequently said to be traversed by means of three vehicles (Skt.yana/Tib.theg-pa): the hinayana, bodhisattvayana and Vajrayana.  The hinayana comprises basic Buddhist teachings deriving from early Buddhism, especially the teachings on the wheel of life (samsara), its causal processes as outlined in the doctrine of interdependent origination (pratityasamutpada), its characteristics - suffering, impermanence, no essential self nature - and the necessity for renunciation of samsara and going for Refuge to the Buddha, Dharma and Sangha.  The bodhisattvayana is the way of the bodhisattva, integrating wisdom and compassion, as taught in the Mahayana Sutras.  The bodhisattva path entails the development of generosity, morality, patience, energy and meditation, infused with transcendent wisdom, through which the "emptiness" of all phenomena is recognised.  The Vajrayana emphasises the imminence of the goal of Enlightenment, and uses powerful techniques to reveal Buddhahood: the emotional poisons, to be rejected or negated at earlier stages, are transmuted and their energies used in overcoming obscurations to Enlightenment.  Various ritual, yoga and meditation practices are used, although their efficacy is dependent on a direct transmission from a Vajrayana master - hence the centrality of the "root lama" in Tibetan Buddhism.
            The various schools developed from teaching lineages which were traced back to different Indian Buddhist masters and traditions (see chart).  Much of the Mahayana and Vajrayana heritage was shared by the different schools: their distinctiveness was in terms of which tantras they practised and the differences in the relative emphasis they put on the gradual methods of the bodhisattva practice and scholarship, as opposed to the swifter methods of tantric meditation.

Buddhism was introduced from India into Tibet much later than other countries which have maintained Buddhist traditions until modern times.  Although Tibetan Buddhism primarily represents the Indian Mahayana and Vajrayana synthesis of the Pala era, it preserved a full range of Indian Buddhist literature and practices deriving from different periods, all of which were collected by Tibetans travelling to the Indian Buddhist centres or brought to Tibet by Indian teachers in the period before Buddhism was extinguished in its homeland.  The monastic code preserved by Tibetan monks, for example, is from the Mulasarvastivadin tradition.  
            Buddhism had first been introduced by the Kings of the Yar-lung dynasty from the seventh century CE; after their demise, large monastic centres were not maintained but there was small-scale Buddhist practice, often centred around hereditary lineages of meditation masters.  From the eleventh century, noble patronage led to more substantial monastic establishments and gradually, these Buddhist monasteries became wealthy in their own right.  Much of Tibetan history concerns the fluctuating fortunes of different regional powers, each associated with one of the Buddhist schools; periods in which power was relatively centralised and large areas integrated into a state structure were followed by periods in which there was little central authority.  In the absence of strong government, the monasteries gained at the expense of the old nobility.  Lamas were frequently involved in dispute settlement and were able to assume political prominence; in the thirteenth century, for example, the Sa-skya-pa head lama represented the Tibetans to avert a Mongol invasion, and his successor became the "ruler" of Tibet under Mongol overlordship.  Lamas of other traditions wielded political power at other times.  There were several alternative methods for appointing important lamas: the one which become most popular and dominant was the institution of the sprul-sku - a monastery's reincarnating lama - which was adopted by the Karma bKa'-brgyud-pa school in the thirteenth century.  From the mid-eighteenth century, the dGe-lugs-pa order dominated the government in Central Tibet.  The other schools nonetheless continued to maintain their centres and the meditative and yogic traditions were never eclipsed by the relatively scholastic and clerical hierarchies of the major monasteries.  A new period began with the Chinese invasion of Tibet in 1950 (see chart).

Tibetan Buddhism has rich and complex ritual symbolism: imagery, sounds and meditation are used to induce physical, vocal and mental transformation so that enlightened realisation is activated.  Some practices focus on the visualisation of Buddhas or Vajrayana deities (representing a specific aspect of Enlightenment, such as compassion, insight or power) and ritual activities (eg. prostrations, offerings) to exhort the manifestation of divine qualities.  Such practices may entail an identification between the practitioner and the divine form meditated upon.  The various symbols - divine images, ritual implements and musical instruments, elaborate ritualised hand gestures, symbolic sculptures (gtor-ma) representing the deity's "palace" or visualised offerings - are all seen as "supports" (rten) for the meditation.  Other practices use yogic imagery of the channels and flows of energy within the body, while some practices dispense with such symbols altogether.  For example, Mahamudra ("Great Symbol") meditation or rDzogs-chen ati-yoga are essentially formless meditation practices.

Most Tibetans in Tibet and the ethnically Tibetan areas under Chinese control (perhaps about four million people) are Tibetan Buddhists, as are a large percentage of the Tibetan exile community of about 130,000.  Many of the Tibetan speaking peoples who live in the himalayan areas within India (such as Ladakh, Spiti, Lahul), in Nepal and in Bhutan are also Tibetan Buddhists.  Some non-Tibetans also follow Tibetan Buddhism - Tibetan Buddhism had been established in Mongolia in the pre-modern era, and now, exiled lamas are active in teaching East Asian and Western followers.

Each Tibetan Buddhist school has its own head lama(s) and centre.  To some extent, especially in the modern context, the Dalai Lama (based in Dharamsala, India) is a unifying focal figure for Tibetan Buddhists but he has no formal authority over the different Buddhist orders and the Chinese Government do not allow him to play an active role in Buddhism in Tibet.  The address of the Office of H.H. The Dalai Lama is Thekchen Choeling, Mcleod Ganj, Dharamsala, District Kangra, Himachal Pradesh, India, 176219.