This qualitative study used semistructured interviews to describe adolescents' responses at 7 and 13 months to siblings' neonatal intensive care unit/pediatric intensive care unit/emergency department death. At 7 months, adolescents were asked about events around the sibling's death; at 7 and 13 months, they were asked about concerns/fears, feelings, and life changes. Seventeen adolescents participated (13-18 years; mean,15 years); 65% were black, 24%, Hispanic, and 11%, white. Themes included death circumstances, burial events, thinking about the deceased sibling, fears, and life changes. Adolescents reported shock and disbelief that the sibling died; 80% knew the reason for the death; many had difficulty getting through burials; all thought about the sibling. From 7 to 13 months, fears increased, including losing someone and thoughts of dying. Adolescents reported more changes in family life and greater life changes in them (more considerate, mature) by 13 months; some felt that friends abandoned them after the sibling's death. Girls had more fears and changes in family life and themselves. Adolescent's responses to sibling death may not be visually apparent. One recommendation from this study is to ask adolescents how they are doing separately from parents because adolescents may hide feelings to protect their parents, especially their mothers. Older adolescents (14-18 years) and girls may have more difficulty after sibling death.