Over the decades of its presence in science fiction (SF) megatext, the sentient spaceship trope, started by James Blish’s short story “Solar Plexus” (1941), has developed variations, including mechanical, human, nonhuman animal and AI elements. The merging of the ontologically diverse elements in sentient spaceships’ bodies creates an intersection of different aspects of otherness, providing a common ground for the exploration and comparison of the attitudes to the cyborg, the animal other, and the technological other, encapsulated in SF narratives. Selected SF short stories, novels, series, films, and TV shows, featuring sentient spaceships and delving into their subjectivity, are analysed through close reading, and putting these works into genre, historical, and social contexts. The dissertation applies posthumanism and new materialism as critical lenses. Rosi Braidotti describes the drive to challenge traditional dualisms and anthropocentric premises as central for posthumanism. The sentient spaceship blurs boundaries between the human and nonhuman, the body and mind, nature and culture. Donna Haraway’s concepts of companion species and kinship are employed to analyse relations between the human and the sentient spaceship, and relations between different species within sentient spaceships’ bodies, interrogating the anthropocentric perspective. The interaction of sentient spaceships and humans are indicative of the presence of the nonhuman agency, which is contemplated engaging with Karen Barad’s agential realism and Jane Bennett’s vibrant matter. The dissertation classifies sentient spaceships according to the elements their bodies contain and follows the evolution of the attitudes towards the human and nonhuman expressed through the trope. The trope starts with the human as a central element in Golden Age SF, situating humanness as the main parameter, against which the value of the other is defined. Later works venture into more diverse representations where anthropocentrism is criticized, and more equal and just ways of human/nonhuman interaction are explored.