Disturbed peer relationships have commonly been found to have long-lasting adverse impacts on children, including school dropout, substance abuse, criminal offenses, psychological maladjustment, and academic problems (Mrug et al., 2012). One subgroup of children wellknown to struggle with their peer relationships are children with Attention-deficit/Hyperactivity Disorder (Hoza, 2007). These children often engage in high rate, intrusive behaviors and are excluded from peer interactions (Hoza et al., 2005). The frequent rejection that these children endure highlights the need for research focused on ostracism, the exclusion or ignoring of others by individuals or groups (Williams, 2007). Thus, the purpose of the current study was to examine the effects of ostracism among children with varying levels of ADHD symptom severity.Further, several social-cognitive factors were examined to determine how they impacted boys' reaction to ostracism, including achievement orientation and positive illusory bias.Fourth through 9 th grade boys (N = 76) completed several assessments and played a computer game with e-confederates who left the participating boy out of the game. Boys' responses to ostracism were assessed in a variety of ways. To determine persistence, responses to ostracism were measured by number of words written in a letter-writing task, as well as number of adjectives and adverbs used, amount of time spent crafting the letter, and number of topics used. Boys high in ADHD symptom severity with a strong mastery orientation used more time in their second letters, whereas boys high in ADHD symptom severity with a strong performance orientation used more words in their second letters. Positive illusory bias was not linked to any persistence outcomes. Mastery and performance orientation showed differential impacts on persistence for boys following ostracism.