Abstract Background Allonormative beliefs entail the idea that all people desire sexual activity with other people. Single and/or asexual individuals may face social disapproval or discrimination for not being in line with allonormative beliefs. The present study investigated whether individuals offered help or were likely to befriend a new co-worker differently depending on the co-worker’s sexual orientation (i.e., heterosexual vs. asexual) and relationship status (i.e., in a relationship vs. single). Methods The online study included 1,028 participants (50.0% women and 50.0% men; Mage = 29.2, SD = 8.8) from German-speaking countries. Each participant read one of twelve short descriptions of a working situation in which they got to know a new co-worker. The description of the new colleague’s gender, sexual orientation, and relationship status varied. Participants had to indicate how likely they would share information with, befriend, gossip about, or have other-interests in the new colleague. A multivariate analysis of co-variance was calculated. Results Female participants had lower intentions to share knowledge with persons who were singles by circumstance than with persons in a relationship and male participants were more likely to befriend a single gay man by choice than a gay man in a relationship. Conclusions Bias against single persons or prejudice resulting from heteronormative beliefs might lead to subtle differences in behavior towards a co-worker. Such subtle “micro-practices” can be harmful because micro-practices accumulate over time and situations. Interventions at organizations need to help employees realize their own biases that might be based on prejudices against people with different sexual orientations and relationship statuses. Key messages • Overall women are more pressured by allonormative ideas and might therefore have lower intentions to share knowledge with persons who were singles by circumstance than with persons in a relationship. • The differing treatment of single gay men by choice and gay men in relationships may not be solely due to adherence to allonormativity, but rather could stem from heterosexist beliefs.