Discrimination against asexual people, also known as acephobia or aphobia when directed at aro/ace (aromantic and/or asexual) people, encompasses a range of negative attitudes, behaviours, and feelings toward asexuality or people who identify as asexual. Negative feelings or characterisations toward asexuality include dehumanisation, the belief that asexuality is a mental illness, that asexual people cannot feel love, and the refusal to accept asexuality as a genuine sexual orientation. Asexuality is sometimes confused with celibacy, abstinence, antisexualism, or hyposexuality. As a form of discrimination on the basis of sexual orientation, acephobia belongs under the wider social concept of kyriarchy.

There have been efforts to combat anti-asexual discrimination through legislation or education (such as through workshops on asexuality).

Behaviours and attitudes that are considered discriminatory include the idea that asexuality is a mental illness, that asexuality is a phase or a choice, the idea that asexual people cannot feel love, and those that make asexual people feel dehumanised. Asexuality would also be perceived as an "excuse" to disengage in certain social interactions, making asexual people a socially rejected group since they are associated with negative social traits. Aspects of discrimination experienced can depend on other parts of one's identity. Despite an increase in media attention over the years, asexuality remains widely poorly-understood; one Sky News survey found that 53% of 1,119 respondents felt confident in defining asexuality, but that 75% of this group did so incorrectly, or defined asexual people as simply lacking a libido.

Asexual people sometimes face discriminatory or dismissive attitudes or behaviours both within and beyond the LGBT community. In 2011, LGBT activist Dan Savage stated that asexuality was a choice, describing it as "choosing not to have sex" and deeming it unworthy of attention.

Ruth Westheimer, a sex therapist, professor, and author, also faced criticism by some for her view that the ability to achieve orgasm would mean that a person could not be asexual, and was further criticized by some in 2015 for implying that asexuality was a problem in need of solving. A study on 169 asexual people published in April 2016 by Yale University found that many encountered dismissal and scepticism on coming out. There have been efforts to stop the exclusion of asexuals from LGBT pride events.

Asexual people whose asexuality has been accepted only because there is no other explanation for their lack of interest in sexual activity have come to be known as "unassailable asexual[s]". Disbelieving attitudes towards asexuality can leave asexual people afraid to come out.

A 2017 LGBT survey conducted by the Government of the United Kingdom found that 2% of more than 108,000 respondents identified as asexual. Asexual people had the joint-lowest (alongside pansexual people) average life satisfaction of any sexual orientation amongst cisgender respondents. The results of the survey also showed asexual people to be the least comfortable cisgender LGBT group within the United Kingdom, and 89% of cisgender asexual respondents – the highest percentage of any group surveyed – were reluctant to be open with their identity for fear of negative reactions.

Asexual people may be socially discriminated against due to beliefs of heterosexuality being the default sexuality, or the belief that asexual people are just gay or lesbian people in denial of their "real" identity. Some have argued that asexuality has also been used as a tool in anti-Blackness to "de-sexualise" some Black people through racist stereotypes, such as in the mammy archetype in the United States.