OBJECTIVE: To examine whether difficulties in emotional, attention, and peer or social functioning (a proposed "preterm behavioral phenotype") co-occur within individual children born extremely preterm (EP; <28 weeks of gestation) and/or extremely low birth weight (ELBW; <1,000 g) and whether different behavioral profiles are related to cognitive and academic outcomes. METHODS: Population-based cohort of all EP/ELBW survivors born in the state of Victoria, Australia, in 2005, and contemporaneous matched controls were recruited at birth. At age 7 to 8 years, parents of 181 EP/ELBW and 185 control children rated their children's behavior on the Strengths and Difficulties Questionnaire problem scales (emotional symptoms, conduct problems, hyperactivity/inattention, and peer problems). Latent profile analysis was used to explore patterns of behavior within individual children. RESULTS: Four behavioral profiles were identified: (1) minimal difficulties in all domains; (2) a profile consistent with the preterm behavioral phenotype; (3) elevations in all domains except peer problems; and (4) marked global elevations in all domains. Most preterm children (55%) had a profile of minimal difficulties. Relative to their risk of being in the minimal difficulties group, EP/ELBW children were overrepresented in the preterm behavioral phenotype (20% vs. 12% controls) and the globally elevated symptom groups (8% vs. 3%). Accounting for birth group and demographic variables, profiles with higher levels of behavior symptoms were associated with poorer cognitive and academic performance. CONCLUSION: Although more EP/ELBW children exhibited the proposed preterm behavioral phenotype than controls, it occurred in only 20% of EP/ELBW children. Greater behavior symptoms were associated with poorer cognitive and academic outcomes.