Mindfulness and acceptance-based psychotherapies have gained popularity in the last few decades as a “third wave” of cognitive behavioral therapy (CBT). Acceptance is an important factor in all of these psychotherapies and stems from Asian philosophies, therefore similarities are necessarily seen between the psychotherapies themselves. This paper aims to demonstrate the ways in which acceptance-based psychotherapies converge by virtue of sharing the same philosophical root, as well as how they diverge in their applications of this concept. Specifically, this paper will examine similarities and differences in the concept of acceptance amongst the therapeutic models of rational emotive behavior therapy (REBT), dialectical behavior therapy, acceptance and commitment therapy, and mindfulness-based cognitive therapy, as compared to the Asian philosophical traditions of Buddhism and Hinduism. Acceptance in these psychotherapies will first be collectively compared with that of the Asian philosophical traditions, then key similarities and differences will be highlighted among the psychotherapies themselves. A secondary aim of this paper is to illustrate REBT as an acceptance-based psychotherapy, though it is not often included in discussions of third wave acceptance-based CBTs.