Buddhism is a Religion and Philosophy focusing on the teachings of the Gautama Buddha. He probably lived from the latter half of the sixth to the early 5th century BCE. Buddhism spread throughout the ancient India sub-continent in the Timeline of Buddhism following the Buddha's death, and propagated into Central Asia, Southeast Asia and East Asia over the next two millennia. Today, Buddhism is divided primarily into three traditions: Theravada, Mahayana  and Vajrayana. Buddhism continues to attract followers worldwide, and, with around 350 million followers, it is considered a Major world religion.

(From Wikipedia, the free encyclopedia)  

There are two main lineages of Buddhist teachings, Theravada and Mahayana.

Theravada (Pali language for The Teaching of The Elders) is the main form of Buddhism practiced in Thailand, Burma, Laos, Cambodia and Sri Lanka. The earliest known teachings of the Buddha are in Pali and are from the Theravadin school.

Mahayana (The Great Vehicle) covers many schools, including Tantra (the secret teaching of Yoga) found in Tibet and Nepal through Yogacara, Avatamsaka, Madhyamika, T’ien T’ai and Ch’an to Pureland Buddhism.  Mahayana monks and nuns undertake the Bodhisattva Vow, to be a person who delays their own enlightenment to help all living beings reach theirs. Eventually they become Bhuddas.
  Vajrayana (the Thunderbolt Vehicle) is found in Tibet, Bhutan, Mongolia and Nepal. Vajra is a symbol of diamond, of thunder and lightning. The Lama (Tibetan for guru) is the central religious figure. Sects include Gelug-pa (H.H. Dalai Lama), Kagyu-pa (Diamond Way) and Nyingma-pa (The Tibetan Book of the Dead).
  Japanese Buddhism includes the branches Zen (Soto and Rinzai), Tendai, Shingon and Pure Land.
  Chinese Buddhism includes the branches Kosa, Satysiddhi, Lotus, Chen Yien and Ch’an.