This dissertation articulates the ways that thinking and feeling with "trans affect" promises better understandings of experiences of trans embodiment. First examining key intellectual debates in feminist, queer, and trans theories about the inheritances and formations of "transgender" and trans, the dissertation explores ties between these conversations and discussions in feminist science studies about knowledge politics. Arguing that attention to "affect," or feeling as bodily movement and emotion, promises better ways to get at the lived experiences of trans people, the dissertation focuses on the role of specifically "trans affect" as a means to understand the kinds of transformations and emergent knowledges that trans experiences promise. Close readings of the role of "trans affect" in work by Aleshia Brevard, Leslie Feinberg, and Susan Stryker reveal the ways that "trans affect" can prompt transformations in not just methods of reading and understanding, but also in the knower who seeks its touch. The writing concludes by articulating how the mode of attention that inheres in "thinking and feeling with trans affect" can and should be brought into other projects in ontology and epistemology.