Ösel Tendzin (Tibetan: འོད་གསལ་བསྟན་འཛིན་, Wylie: `od gsal bstan `dzin) (1943–1990) was a western Buddhist. He was Chögyam Trungpa's principal student. On August 22, 1976, Chögyam Trungpa empowered Ösel Tendzin as his Vajra Regent and first Western lineage holder in the Tibetan Karma Kagyü and Nyingma lineages. On August 25, 1990, Ösel Tendzin died of HIV in San Francisco, California. His wife, Lila Rich, and a group of his students continue to live in Ojai, California.
Tendzin was born Thomas Frederick Rich, Jr. on June 28, 1943 in Passaic, New Jersey. He graduated in 1965 from Fordham University, initially working as a physical therapist in New York and Los Angeles. Before joining Vajradhatu he studied with Swami Satchidananda, who gave him the name Narayana.
Tendzin first met Trungpa in February 1971 in Boulder, Colorado. According to Tendzin, Trungpa revealed his intention to make Tendzin his successor not long after their initial meeting. Starting in 1973 Tendzin held various roles in the management of Vajradhatu. He served on the initial board of directors and as an executive vice-president of the organization. In April 1976, Tendzin's Regency was announced to the community for the first time. Trungpa recounted the moment in a later edition of his memoir, writing "to ensure that everything will not stop at my death, it is necessary to have one person as an inheritor, someone whom I can train and observe over a period of many years. For a long time it was in my mind to appoint Narayana to this role, and in the summer of 1976 I did so, empowering him as Dorje Gyaltsap, Vajra Regent.” 
In his forward to the Tendzin's 1987 book Buddha in the Palm of Your Hand, Trungpa elaborated on his decision:
As a student and child of mine, Ösel Tendzin has developed his natural ability to respond to the teachings of egolessness. He not only intellectually comprehends these teachings, but he has actually practiced and trained himself in this way. Although I would not say Ösel Tendzin is an enlightened person, he is one of the greatest examples of a practitioner who has followed the command of the Buddha and his guru and the tradition of the Practice Lineage.
Many Oriental advisors have said to me, ‘Do not make an Occidental your successor; they are not trustworthy.’ With the blessings of His Holiness the 16th Gyalwa Karmapa, and through working with Ösel Tendzin as my Regent, I have come to the conclusion that anybody who possesses tathagatagarbha is worthy of experiencing enlightenment. Moreover, Ösel Tendzin is my prime student. He has been able to commit himself and learn thoroughly the teachings of vajrayana. I have worked arduously in training him as my best student and foremost leader, and His Holiness Karmapa has confirmed his Regency. With His Holiness’ blessing, Ösel Tendzin should hold his title and the sanity of the enlightened lineage. He is absolutely capable of imparting the message of buddhadharma to the rest of the world.
In 1989 Tendzin moved to Ojai, California with some of his students. After his death, those students led by Patrick Sweeney — who Tendzin chose as his lineage holder and successor — created an organization called Satdharma. It was formally incorporated in 1992 to continue Tendzin's lineage, separate from Vajradhatu.
Among the controversial actions of Tendzin was his rejection of the recommendation of senior Kagyu lineage holder Tai Situ Rinpoche that Tai Situ take over leadership of Vajradhatu in conjunction with Trungpa's half brother Damchu Tenphel Rinpoche, who resided in Tibet. This was "regarded by members as a serious slight to lineage authorities and was construed as the Regent's attempt to secure his position of control." Also controversial was the fact that he "took further action to buttress his centrality by denying students permission to seek teachings from other Kagyu Tibetan teachers, claiming that only he possessed the special transmission, materials and knowledge unique to the Trungpa lineage. Students were told that if they wanted to practice within the community, they would have to take spiritual instruction from the Regent."
Other behavior was troubling as well. As one scholar who has studied the community noted, Tendzin was "bisexual and known to be very promiscuous" and "enjoyed seducing straight men" but the community "did not find [this behavior] particularly troublesome." Not all his partners were unwilling; one scholar noted "it became a mark of prestige for a man, gay or straight, to have sex with the Regent, just as it had been for a woman to have sex with [Trungpa] Rinpoche." However, at least one student reported that Tendzin had raped him. As a former Vajradhatu member attested, "a chilling story had recently been reported by one of . . .[the] teachers at the Buddhist private school [for the Vajradhatu community]. This straight, married male was pinned face-down across Rich's desk by the guards [the Dorje Kasung] while Rich forcibly raped him."
It was revealed in 1989 that Ösel Tendzin had contracted HIV, and for nearly three years knew it, yet continued to have unprotected sex with his students, without informing them. He transmitted HIV to a student who later died of AIDS. Others close to Tendzin, including the board of directors of Vajradhatu, knew for two years that Tendzin was HIV-positive and sexually active, but kept silent. As one student reported at the time,
I was very distressed that he and his entourage had lied to us for so long, always saying he did not have AIDS. I was even more distressed over the stories of how the Regent used his position as a dharma teacher to induce "straight" students to have unprotected sex with him, while he claimed he had been tested for AIDS but the result was negative.
Stephen Butterfield, a former student, recounted in a memoir:
Tenzin offered to explain his behavior at a meeting which I attended. Like all of his talks, this was considered a teaching of dharma, and donations were solicited and expected. So I paid him $35.00 to hear his explanation. In response to close questioning by students, he first swore us to secrecy (family secrets again), and then said that Trungpa had requested him to be tested for HIV in the early 1980s and told him to keep quiet about the positive result. Tendzin had asked Trungpa what he should do if students wanted to have sex with him, and Trungpa's reply was that as long as he did his Vajrayana purification practices, it did not matter, because they would not get the disease. Tendzin's answer, in short, was that he had obeyed the guru."
Butterfield noted, "Tendzin's account of his conversations with Trungpa was challenged by other senior disciples, who claimed Trungpa would never have led anyone to believe that the laws of nature could be suspended by practice." Butterfield also wrote, "it was a difficult dilemma: if you chose to believe Tendzin, then Trungpa had simply been wrong in telling him he could not transmit the disease . . but what then became of the axiom that the guru cannot make a mistake? But if you chose to disbelieve Tendzin, then Trungpa may have been wrong in allowing him to remain Regent, or perhaps in choosing him at all... I heard Tendzin's illness explained by his servants in this way: it was not a consequence of any folly or self-indulgence on his part, but the karma of his infected partners, that he had deliberately imbibed for them. In what way they benefitted was never made clear to me, although one could safely assume the benefits did not include physical cure."
According to Diana Mukpo, wife and widow of Trungpa, he ultimately became disillusioned with Tendzin as his heir, and during his final illness he called Tendzin "terrible" and "dreadful", and indicated that he would have gotten rid of Tendzin had he a suitable candidate with which to replace him. Rick Fields, the editor of Vajradhatu's publication the Vajradhatu Sun, wrote that he resigned from his editorial position after Ösel Tendzin and the Board of Directors stopped him from publishing news of the events.
- Buddha in the Palm of Your Hand, Shambhala Publications. Boston, 1982. 0-87773-223-X
- Space, Time and Energy, Vajra Regent Ösel Tendzin, Satdharma Publications, 2000.
- Like Water Poured into Water, Vajra Regent Ösel Tendzin, Foreword by Lady Lila Rich; Introduction by Patrick Sweeney, Satdharma Publications, 2006.
- "Satdharma biography of Tendzin".
- Dewitte Lindsey (2003). Tibet to Texas: A Grassroots History of Karma Kagyu Buddhism in the Lone Star State. Sunbelt Eakin. ISBN 978-1-57168-691-6. "Thomas Rich would die three years later from HIV, a disaster for both his unsuspecting partners and the entire Vajradhatu community."
- "Shambhala teachers biography for Tendzin".
- Midal, Fabrice. Chögyam Trungpa: His Life and Vision. Shambhala, 2004. ISBN 1-59030-098-X pg 437
- Midal, Fabrice. Chögyam Trungpa: His Life and Vision. Shambhala, 2004. ISBN 1-59030-098-X pg 440
- ’’Born in Tibet, 4th edition,’’ by Chogyam Trungpa. Shambhala Publications: 2000. pg 263
- Buddha in the Palm of Your Hand by Osel Tendzin Shambhala Publications: 1987. ISBN 0-87773-223-X pgs xii-xiii
- "Sweeney biography on Satdharma".
- Eldershaw 2004, p. 229
- Eldershaw 2004, p. 230
- Eldershaw 2004, p. 226
- Kane, Stephanie. AIDS Alibis: Sex, Drugs, and Crime in the Americas. Temple University Press, 1998. p. 154
- Eldershaw 2004, pp. 228, 230
- Steinbeck 2001, p. 311
- New York Times (1989)
- Hayward (2007) p. 407-409
- Butterfield (1994)
- Dart (1989)
- Steinbeck 2001, pp. 279, 311
- Coleman 2001, p. 170
- Butterfield p. 183
- Butterfield p. 184
- Butterfield p. 186
- Mukpo p. 378
- Fields (1992) p. 366
- Butterfield, Stephen T. (1994). The Double Mirror: A Skeptical Journey into Buddhist Tantra. ISBN 1-55643-176-7
- Coleman, James William. The New Buddhism: The Western Transformation of an Ancient Tradition (2001) Oxford University Press. ISBN 0-19-513162-2
- Dart, John (1989) "Buddhist Sect Alarmed by Reports that Leader Kept his AIDS a Secret", The Los Angeles Times, March 3, 1989 link
- Eldershaw, Lynn P. "Collective identity and the post-charismatic fate of Shambhala International" 2004 Ph. D. thesis, University of Waterloo; also, an article drawn from this thesis was published in Nova Religio: The Journal of Alternative and Emergent Religions, (2007) Vol. 10 No. 4, pp. 72–102, ISSN 1092-6690
- Fields, Rick (1992). How the Swans Came to the Lake. ISBN 0-87773-631-6
- Hayward, Jeremy (2007) Warrior-King of Shambhala: Remembering Chogyam Trungpa ISBN 0-86171-546-2
- Mukpo, Diana (2006). "Dragon Thunder: My Life with Chogyam Trungpa" ISBN 978-1-59030-256-9
- Steinbeck, John Steinbeck IV and Nancy (2001). The Other Side of Eden: Life with John Steinbeck Prometheus Books. ISBN 1-57392-858-5
- Week in Review Desk, "HEADLINERS; A Church's Turmoil," The New York Times, February 26, 1989 link