Modern yoga is a wide range of yoga practices with differing purposes, encompassing in its various forms yoga philosophy derived from the Vedas, physical postures derived from Hatha yoga, devotional and tantra-based practices, and Hindu nation-building approaches.

The scholar Elizabeth de Michelis proposed a 4-part typology of modern yoga in 2004, separating modern psychosomatic, denominational, postural, and meditational yogas. Other scholars have noted that her work stimulated research into the history, sociology, and anthropology of modern yoga, but have not all accepted her typology. They have variously emphasised modern yoga's international nature with its intercultural exchanges; its variety of beliefs and practices; its degree of continuity with older traditions, such as ancient Indian philosophy and medieval Hatha yoga; its relationship to Hinduism; its claims to provide health and fitness; and its tensions between the physical and the spiritual, or between the esoteric and the scientific.

In the early years of British colonialism in India, the elites from the United States, Europe, and India rejected the concept of hatha yoga and perceived it as unsociable. By the late 19th century, yoga was presented to the Western world in different forms such as by Vivekananda and Madame Blavatsky. It embodied the period's distaste for yoga postures and hatha yoga more generally, as practised by the despised Nath yogins, by not mentioning them. Blavatsky helped to pave the way for the spread of yoga in the West by encouraging interest in occult and esoteric doctrines and a vision of the "mystical East". She had travelled to India in 1852-53, and became greatly interested in yoga in general, while despising and distrusting hatha yoga. In the 1890s, Vivekananda taught a mixture of yoga breathwork (pranayama), meditation, and positive thinking, derived from the New Thought movement, again explicitly rejecting the practice of asanas and hatha yoga.

A few decades later, a very different form of yoga, the prevailing yoga as exercise, was created by Yogendra, Kuvalayananda, and Krishnamacharya, starting in the 1920s. It was predominantly physical, consisting mainly or entirely of asanas, postures derived from those of hatha yoga, but with a contribution from western gymnastics (such as Niels Bukh's 1924 Primary Gymnastics and the harmonial gymnastics of women such as Genevieve Stebbins, Annie Payson Call, and Mary (Mollie) Bagot Stack). They advocated this form of exercise under the guise of the supposed specific medical benefits of particular postures, quietly dropping its religious connotations, encouraged by the prevailing Indian nationalism which needed something to build an image of a strong and energetic nation. The yoga that they created, however, was taken up predominantly in the English-speaking world, starting with America and Britain.

The popularity of modern yoga increased as travel became more feasible, allowing exposure to different teachings and practices. Immigration restrictions were relaxed from India to the USA and some parts of Europe around the 1960s. And, spiritual gurus began to offer what they referred to as solutions to the problems of modern life. As new-age high profile individuals, such as the Beatles, tried out yoga, the practice became more visible and desirable as a means to improve life.

The idea of yoga as "modern" was current before any definition of it was provided; for example, the philosopher Ernest Wood referred to it in the title of his 1948 book Practical Yoga, Ancient and Modern. Elizabeth de Michelis started the academic study of modern yoga with her 2004 typology. She defined modern yoga as "signifying those disciplines and schools which are, to a greater or lesser extent, rooted in South Asian cultural contexts, and which more specifically draw inspiration from certain philosophies, teachings and practices of Hinduism." With Vivekananda's 1896 Raja Yoga as its starting point, her typology of yoga forms as seen in the West, explicitly excluding forms seen only in India, proposed four subtypes.

From the 1970s, modern yoga spread across many countries of the world, changing as it did so, and in De Michelis's view becoming "an integral part of (primarily) urban cultures worldwide", to the extent that the word yoga in the Western world now means the practice of asanas, typically in a class.

Mark Singleton, a scholar of yoga's history and practices, states that De Michelis's typology provides categories useful as a way into the study of yoga in the modern age, but that it is not a "good starting point for history insofar as it subsumes detail, variation, and exception". Singleton does not subscribe to De Michelis's interpretative framework, instead considering "modern yoga" to be a descriptive name for "yoga in the modern age". He questions the De Michelis typology as follows: