Publishers and academics have had a hard time categorizing Kindred. In an interview with Randall Kenan, Butler stated that she considered Kindred “literally” as “fantasy.” According to Pamela Bedore, Butler's novel is difficult to classify because it includes both elements of the slave narrative and science fiction. Frances Smith Foster insists Kindred does not have one genre and is in fact a blend of “realistic science fiction, grim fantasy, neo-slave narrative, and initiation novel.” Sherryl Vint describes the narrative as a fusion of the fantastical and the real, resulting in a book that is "partly historical novel, partly slave narrative, and partly the story of how a twentieth century black woman comes to terms with slavery as her own and her nation's past."
Critics who emphasize Kindred’s exploration of the grim realities of antebellum slavery tend to classify it mainly as a neo-slave narrative. Jane Donawerth traces Butler's novel to the recovery of slave narratives during the 1960s, a form then adapted by female science fiction writers to their own fantastical worlds. Robert Crossley identifies Kindred as "a distinctive contribution to the genre of neo-slave narrative" and places it along Margaret Walker’s Jubilee, David Bradley’s The Chaneysville Incident, Sherley Anne Williams’s Dessa Rose, Toni Morrison’s Beloved, and Charles R. Johnson’s Middle Passage. Sandra Y. Govan calls the novel "a significant departure" from the science fiction narrative not only because it is connected to "anthropology and history via the historical novel," but also because it links "directly to the black American slave experiences via the neo-slave narrative." Noting that Dana begins the story as a free black woman who becomes enslaved, Marc Steinberg labels Kindred an "inverse slave narrative."
Still, other scholars insist that Butler’s background in science fiction is key to our understanding of what type of narrative Kindred is. Dana’s time traveling, in particular, has caused critics to place Kindred along science fiction narratives that question "the nature of historical reality,” such as Kurt Vonnegut's "time-slip" novel Slaughterhouse Five and Philip K. Dick’s The Man in the High Castle, or that warn against "negotiat[ing] the past through a single frame of reference," as in William Gibson's "The Gernsback Continuum." In her article “A Grim Fantasy,” Lisa Yaszek argues that Butler adapts two tropes of science fiction—time-travel and the encounter with the alien Other—to “re-present African-American women’s histories.” Raffaella Baccolini further identifies Dana's time traveling as a modification of the "grandfather paradox" and notices Butler's use of another typical science fiction element: the narrative's lack of correlation between time passing in the past and time passing in the present.