Bahá'u'lláh teaches the essential oneness of all religions revealed by divinely sent Manifestations, one of Whom is the Buddha. This paper seeks to provide detailed illustrations of these teachings by showing that two different and apparently incompatible religions - the Bahá'í Faith and Buddhism - share fundamental ontological principles. In other words, implicitly and/or explicitly, their analyses of reality and what it means 'to be' are, outward appearances notwithstanding, largely compatible. This means that the Bahá'í Writings converge with and can accommodate the major areas of ontological concern in the various forms of Buddhism: anicca (impermanence), dharma, dependent origination, anatman (no-self), causality, emptiness, non-theism, nirvana and samsara and the nature of the Buddha. The paper provides copious references to the Bahá'í Writings, Buddhist sutras, and works by well-established scholars and writers about Buddhism.