OBJECTIVES: To understand current levels of awareness, usage, and knowledge of biosimilars. METHODS: Interviews (10 to 20 minutes of close-ended questions) were conducted online in adults categorized as: 1) Diagnosed: patients with Crohn’s disease, ulcerative colitis, rheumatoid arthritis, psoriasis, breast cancer, lung cancer, colorectal cancer, or non-Hodgkin’s lymphoma; 2) Diagnosed Advocacy: individuals with these diseases who participated in patient support groups; 3) Caregiver: has a loved one with these conditions and is involved in medical decisions; or 4) General Population: aged 18 to 64 years without (nor loved ones with) these conditions. Groups were analyzed using the column proportions test with a 95% confidence interval. RESULTS: A total of 3,198 individuals responded. Awareness about biologic therapies, defined as the percentage of respondents reporting at least a general impression of biologics or that they knew the term “biologic”, was significantly higher in the Diagnosed, Diagnosed Advocacy, and Caregiver groups (45-78%) than the General Population (27%; P < 0.05). Across all groups, awareness of biosimilars was low with only 6% of respondents from the General Population reporting at least a general impression of biosimilars, although this was significantly higher among respondents in the Diagnosed Advocacy group (20-30%; P < 0.05). Several gaps in respondents’ knowledge about biosimilars were noted including safety, efficacy, and access to these agents. Respondents had generally positive perceptions of clinical trials although some barriers to participation were identified such as concerns about side effects, assignment to placebo rather than an active treatment, and time commitments. CONCLUSIONS: As more biosimilars are becoming approved, this study reinforces that there is still an immediate need to provide education to all stakeholders about general biosimilar education and biosimilar clinical trials. These efforts will support patient choice and ensure that educated and informed decisions are made about the use of biosimilars.