This study addresses the concept of the sign as it appears in the writings of Thomas Hobbes, highlighting the importance the English philosopher attached to it in all of his writings, including in Leviathan, his largest and most important political work. The author addresses the fundamental structures of Hobbes’ philosophical writing, including his work on sense perception, human cognition, and speech. Unlike John Locke’s later use, Hobbes didn’t employ the word “semiotike,” but nonetheless included signs in his studies of sensory perceptions, cognition, and emotions. In doing so, he paved the way for a philosophical study of signs, and was able to provide a reading of the visual aspects of sign through the sensory world; its conceptual features through the cognitive world; and a desire-based understanding of signs felt through emotions. Hobbes also expanded the theory of signs. Not only were they sensory, conceptual, and rational, but through the concept of “arbitrariness,” further defined by Ferdinand de Saussure, they were also subjective and societal. Furtermore, Hobbes went beyond tying signs to language and logic by linking signs with speech.