A value affirmation writing task is a psychological threat-reduction nudge identified by past research to reduce the racial achievement gap within schools (Cohen et al., 2006, 2009). However, racial and economic segregation contribute to the nationwide achievement gap (Orfield et al., 2012; Reardon, 2013). Few studies have specifically examined value affirmation effects for Black, Latinx, and students with disabilities within urban schools where students of color are the numeric majority. The present study employs a value affirmation intervention in four urban schools, and uses 808 students’ self-report surveys to investigate the contribution of psychosocial variables (e.g., belonging, institutional trust, social evaluative threat) towards student outcomes (e.g., student grades and attendance). Spearman and Pearson correlation coefficients were calculated and indicated social evaluative threat in the fall had a small but statistically significant negative relationship with Semester 2 grades (-.12, p < .05). A hierarchical regression demonstrated the value affirmation intervention did not significantly improve end-of-term grades for Black or Latinx students, nor did social evaluative threat effects moderate intervention effectiveness. However, students with disabilities who completed the value affirmation intervention showed an improvement in grades compared to their special education peers who did not complete the exercise (m = 4.11, p < 0.00). Using a quantile regression, attendance for Black, Latinx, and students with disabilities who completed the value affirmation did not significantly differ from students who did not complete the intervention. Finally, the value affirmation intervention did not appear to positively impact students trust or belonging compared to students who did not engage in the intervention. The findings are not consistent with peer-reviewed value affirmation studies (Cohen et al., 2006, 2009), and suggest school context and methodological execution play a critical role when examining social-psychological variables, social evaluative threat effects, and value affirmation nudge interventions. The present study highlights the challenge of scaling threat-reduction interventions in urban schools.