Ultra-processed foods (UPFs) have been shown to play a role in promoting inflammation and oxidative stress(1). Emerging research suggests an association between UPF consumption and neurodegenerative conditions, including multiple sclerosis (MS)(2), an inflammatory neurological and immune-mediated disease. Australian research has unveiled a need for evidence-based MS-specific dietary advice to facilitate self-management of the disease(3). As interest into health impacts of UPFs grows, it is timely and relevant to investigate the MS community’s understanding of UPFs. This study aimed to explore the understanding of UPFs among people living with MS in Australia. We used a sequential, mixed-methods approach to comprehensively assess knowledge and attitudes associated with UPFs among the MS community. We conducted an online survey (Phase 1), followed by in-depth discussion via online focus groups (Phase 2). Phase 1: Participants (n = 64) completed a structured questionnaire via Qualtrics, previously piloted in the general Australian population. The survey collected data relating to socio-demographic characteristics, the ability to identify UPFs using a UPF identification task, and UPF knowledge measured through open-ended questions which were content-analysed. Phase 2: Twelve people living with MS attended one of five focus groups. These were recorded and transcribed verbatim. A general inductive approach was undertaken for thematic analysis using a combination of latent and semantic coding. Phase 1: Mean (SD) age of survey participants was 64 (12.3) years. Most were female (91%), educated beyond Year 12 (89%), and born in an English-speaking country (95%). Eighty-six percent were aware of the UPF term and described UPFs based on ingredients. Twenty-nine percent were unable to correctly identify UPFs, with packaged multigrain bread (53%) and pasta sauce (66%) misclassified most often as non-UPFs. Phase 2: Mean (SD) age of focus group participants was 51 (13.3) years and they were mostly female (83%). Six themes emerged: (1) identifying UPFs (“anything that's more chemical compound than raw ingredient is a red flag to me”); (2) scepticism towards food manufacturers (“UPFs are primarily designed to promote overconsumption”); (3) barriers and facilitators influencing UPF consumption (“when I eat out I accept that I'm going to be eating something ultra-processed”); (4) perceived dis-/advantages of UPFs (“convenience is the big factor”); (5) confusion about where to seek MS-specific dietary advice (“trying to find evidence-based sources rather than just opinions which are everywhere and can be quite conflicting”); and (6) wanting trustworthy advice surrounding UPFs and MS (“it would be nice to have credible, trustworthy, unbiased information for people with MS to make dietary decisions”). These results enhance our understanding of how people living with MS perceive UPFs and may inform evidence-based nutrition interventions. Additionally, they may support the development of clear, tailored messaging to improve dietary awareness and encourage healthier food choices within this population.