Depression is a significant mental health issue for bisexual women. While theory and research indicates that sense of belonging is important for mental health, limited research has investigated this in relation to bisexual women belonging to the LGBTQ + community. Existing research indicates that identification and involvement with the LGBTQ + community is not protective for the mental health of bisexual women. The protective nature of the extent to which bisexual women feel valued and needed within the lesbian community has not been examined. The current study examined the relationships between sense of belonging to the lesbian and heterosexual communities and depressive symptoms among bisexual women. A sample of 306 Australian self-identified bisexual women completed the Center for Epidemiologic Studies Depression Scale and the psychological subscale of the Sense of Belonging Instrument. Results indicated that sense of belonging to each community was related to lower levels of depressive symptoms. Further, levels of belonging to each community interacted, indicating that sense of belonging to the lesbian community was protective for bisexual women with lower, but not higher, levels of sense of belonging to the heterosexual community. Results imply that increasing belonging to the lesbian community is important for bisexual women who do not feel they belong in the heterosexual community. The challenge is how to increase sense of belonging of bisexual women in the lesbian community, where they are exposed to negative attitudes about their sexuality.