The expression “linguistic Kantianism” is widely used to refer to ideas about thought and cognition being determined by language — a conception characteristic of 20th century analytic philosophy. In this article, I conduct a comparative analysis of Kant’s philosophy and views falling under the umbrella expression “linguistic Kantianism.” First, I show that “linguistic Kantianism” usually presupposes a relativistic conception that is alien to Kant’s philosophy (although Kant’s philosophy itself may be perceived as relativistic from a certain point of view). Second, I analyse Kant’s treatment of linguistic determinism and the place of his ideas in the 18th century intellectual milieu and provide an overview of relevant contemporary literature. Third, I show that authentic Kantianism and “linguistic Kantianism” belong to two different types of transcendentalism, to which I respectively refer as the “transcendentalism of the subject” and the “transcendentalism of the medium.” The transcendentalism of the subject assigns a central role to the faculties of the cognising subject (according to Kant, cognition is not the conforming of a subject’s intuitions and understanding to objects, but rather the application of a subject’s cognitive faculties to them). The transcendentalism of the medium assigns the role of an “active” element neither to the external world nor to the faculties of the cognising subject, but to something in between — language, in the case of “linguistic Kantianism.” I conclude that the expression “linguistic Kantianism” can be misleading when it comes to the origins of this theory. It would be more appropriate to refer to this theory by the expression “linguistic transcendentalism,” thus avoiding an incorrect reference to Kant.