The Supreme Court of the United States has long recognized that the vulnerabilities of juvenile offenders merit special protections due to deficits in experience and maturity. Appellate courts assume that Miranda warnings will inform juvenile suspects of their Miranda rights, and allow them to render knowing and intelligent waivers. This study examines Miranda misconceptions of legally involved juveniles (i.e., juvenile detainees and youth mandated to juvenile justice alternative education) at different levels of psychosocial maturity. These juveniles manifested an unexpectedly large frequency of erroneous Miranda beliefs; each group (low, middle, and high maturity) averaged a dozen or more misconceptions, thus overshadowing substantive differences between maturity groups. However, maturity played an important role in the immediate recall of a Miranda advisement. Alarmingly, both low‐ and middle‐maturity groups displayed less than one‐third immediate recall. The high‐maturity group performed better, but still failed to recall almost half of the Miranda concepts. The overall findings are discussed with respect to juvenile Miranda comprehension and reasoning. Copyright © 2014 John Wiley & Sons, Ltd.