Many adolescents with allergy do not receive physician treatment (allergyuntreated). We explored its association with socioeconomic adversities and academic-behavior-health difficulties, which remain unaddressed. This cross-sectional school-based-population study compared the above factors of middle-school adolescents with allergyuntreated and those with treated allergy (allergytreated) (mean age = 13.5 ± 1.2) from north-eastern France. Participants completed a questionnaire collecting socioeconomic adversities (nonintact family, low parents' education, insufficient family income, poor social support, suffered verbal/physical violence, and sexual abuse), low academic performance, excessive screen time, substance use, sleep difficulty, poor physical health, depressive symptoms, suicide attempt, poor quality of life, and allergytreated/allergyuntreated. Logistic regression models showed that allergyuntreated was associated with all the factors considered (sex-age-class-level-adjusted odds ratio (saclOR) reaching 3.94, p < .001) and the risk score (number of main criteria: suffered sexual abuse, excessive screen time, poor quality of life, cannabis use, low parents' education, and poor social support): saclOR 4.75, 9.23, 15.64, and 31.73 (p < .001) for risk scores 1, 2, 3, and ≥4, versus risk score = 0 (pseudo-R2 = 11.1%). Socioeconomic adversities and academic-behavior-health difficulties may be used to detect adolescents with allergyuntreated for care.