This study titled as ―Impact of Incongruous Jail Environment on the Juvenile Prisoners in Selected Jails of Khyber Pakhtunkhwa, Pakistan‖ was conducted with the aim of evaluating the impact of an incongruous jail environment on the multiple aspects of juveniles‘ lives who are undergoing incarceration on charges of different kinds of crime. The study was carried out by using mixed methods research approach with concurrent triangulation strategy. Quantitative data was collected through an interview schedule from 132 juvenile prisoners whereas qualitative data was collected from 50 participants through in-depth interviews (IDIs), including juvenile prisoners, jail staff, probation officers and legal counsels. Quantitative data was analyzed through frequencies and percentages under the uni-variate analysis and chi-square test was applied for the association of dependent and independent variables under bi variate analysis. Qualitative data was analyzed through transcribing the data and identification of themes for interpretation. The results of the quantitative and qualitative data were compared and discussed through the proper procedure of the concurrent triangulation strategy. The findings reveal that different elements of living conditions in the jails were not satisfactory. The association of these different elements was found significant with the well-being of juveniles i.e. the availability of clean drinking water and enough water for other cleaning purposes, unsatisfactory toilet facilities, low quality and lack of proper food and diseases caused by that food. Juveniles complained of unfair attitudes of jail staff who dealt with them in a cruel and humiliating manner. There were no exclusive facilities to house the juveniles like Borstal Institution. Rather than rehabilitative treatment, juveniles faced physical punishment like beating etc. They were fearful of jail staff; experienced unhealthy and unsanitary conditions due to overcrowded jail conditions. Many juveniles had no knowledge about their rights and often did not know they could access free legal assistance from government. They experienced unhealthy and abusive behavior at the hands of jail staff and police and had to bribe jail staff to ensure access to justice agents. Furthermore, juvenile cases were tried at the adult courts where they experienced treatment like adult prisoners, including public hearing of their cases, unsatisfactory trials, and mental suffering from lengthy and costly hearing of their suits. Juveniles complained of multiple problems in view of non-existence of privileges as stated in the Juvenile Justice System Ordinance (JJSO) promulgated in 2000 in Pakistan. Juveniles endorsed that they established relations with adult prisoners and gangs at jail due to the absence of proper check and balance over the interaction of juveniles. This absence led to frankness of juveniles sharing of drugs with adult prisoners and gangs at jail; and physical and financial support to juveniles by these gangsters. Although agents of the justice system did not agree to the above mentioned situation, the jail staff contended as these were going against them. The study recommends promulgation of JJSO in letter and spirit.