Background: Sexually transmissible infections (STIs) are common in Australia among young people. Guidelines recommend diagnosing healthcare providers encourage patients to notify sexual partners of an infection when safe to do so. However, there is little research exploring who else young people decide to disclose an STI diagnosis to, and the support they receive after disclosing a diagnosis. Methods: We conducted an anonymous online survey (open 2nd May -- 21st June 2022) of over 2000 young people (aged 16-29 years) living in Australia. We asked participants about their history of an STI diagnosis. Those who had been diagnosed were asked who they had told about their diagnosis, and were also asked in a free-text question about the reaction they received from the person/people they disclosed their diagnosis. Free-text comments were imported into NVivo 12 and analysed using content analysis. Results: A total of 205 (13.2%; 95%CI 11.6-15.0%) people had been diagnosed with an STI. They had a median age of 25 years (IQR: 22-27). Most were cisgender women (66.3%) and a third (33.7%) were heterosexual. Most commonly, participants had been diagnosed with chlamydia (n=109) followed by herpes (n=48), HPV (n=57), and gonorrhoea (n=40). Almost all (94.6%) had disclosed their diagnosis to at least one person, including partners (73.2%), friends (71.7%), and family (30.7%). Free-text comments largely fell into three themes, outlined in Table 1. Most people received non-judgemental, supportive responses to their diagnosis. However, some described negative responses, usually from upset or angry sexual partners. Several respondents described the impact of disclosing a diagnosis. Some discussed the emotional impact on themselves, while others talked about actions taken by themselves or others after the disclosure of a diagnosis. Conclusions: Partner notification is recognised as an important aspect of STI management. However, there is little research that explores where else young people may go for support after being diagnosed with an STI. We found that many young people disclose a diagnosis to partners and friends, and that for the most part, they receive nonjudgemental and supportive reactions. However, it is clear that many still experience stigma and shame when disclosing a diagnosis. [ABSTRACT FROM AUTHOR]