Attention-deficit/hyperactivity disorder (ADHD) is a common neurobehavioral disorder beginning in childhood and often extending into adulthood. ADHD may negatively impact emotional regulation and cause addictive behaviors such as social media addiction. The present study investigated the association of ADHD symptoms (i.e., attention deficit [AD] and hyperactivity/impulsivity [HI]) with social media addiction among young adults. The mediating effect of internalizing and externalizing emotional regulation (i.e., self-blame [SB] and blaming others [BO]) were examined. Participants (n = 96; mean age = 19.9 years [SD = 2.07]) comprising 35 individuals with probable ADHD and 61 individuals who did not have ADHD completed measures assessing social media addiction, ADHD symptoms, and emotional regulation strategies. Results of Hayes' Process Micro showed that both ADHD symptoms were significantly positively associated with social media addiction (standardized coefficient [β] = 0.30 and 0.38 for AD and HI) and emotional regulation strategies (β = 0.38 and 0.27 for AD to SB and BO, β = 0.23 and 0.28 for HI to SB and BO). In addition, BO was a significant mediator in the association between AD and social media addiction (β = 0.07, 95 % confidence interval = 0.003, 0.11). The results suggest that externalizing emotional regulation may mediate the association between symptoms of AD and social media addiction. It is recommended that individuals with probable ADHD should focus on improving self-awareness (such as mindfulness), developing resilience skills, and/or incorporating positive coping strategies (such as physical activity) to reduce the negative impacts derived from symptoms of ADHD.