Objectives Recently, research has focused on understanding the needs of persons with early‐onset dementia and their family caregivers who often experience stigmatic beliefs. However, to date, research has not provided a thorough and deep understanding of the stigma formation process and its implications for this population. Thus, the aim of the present study was to explore the stigma formation process as experienced by family members as informal caregivers of persons with early‐onset dementia, and professionals as formal caregivers who are involved in the development, management and provision of services. Method We conducted three focus groups with 16 participants, including spouses of a person with early‐onset dementia and professionals. The focus groups’ transcripts were analysed following a thematic analysis procedure. Results Results indicated that both family members and professionals encounter stigmatic experiences because of their association with younger persons with dementia. Lack of knowledge emerged as the main antecedent and emotional burden as the main consequence of stigma. Conclusion Stigmatic experiences emerged as a pervasive and complex phenomenon among formal and informal caregivers of persons with early‐onset dementia, suggesting the need to developing a comprehensive and integrated approach to reduce them at the individual, professional and societal levels.