In the last couple of decades Islamic banking has adapted significantly to the constraints and thus sustained and grew. This thesis aims to describe the obscured adaptations in the Islamic banking to the prevailing constraints and the outcomes of these adaptations, within the Islamic participatory financing cases as evidence. Participatory financing arrangements including Musharakah and Mudarabah are believed to be the ideal modes of financing as prescribed within extensive Islamic finance literature. Therefore, Islamic banks are, usually, expected to apply participatory financing. In practice, however, the participatory financing is not dominant, primarily, because it is constrained by its inherent uncertainty, it has weak regulation particularly related to its operations, and it has lower demand, as the thesis found in the literature. Recently, however, the makeup of financing portfolio of Islamic banks has shown significant growth in the share of participatory financing. This thesis claims that this growth is because of adaptation in participatory financing to the underlying constraints. The thesis, therefore, aims to theoretically and empirically develop a framework to conceptualize the constraints to participatory financing, the responding adaptation to the constraints, and its outcomes. Three interrelated research objectives are set for this purpose. Firstly, a typology of constraints to the participatory financing is developed through a rigorous systematic literature review and is presented as pre-empirical framework. This typology is important for understanding the adaptation to constraints and its outcomes. Ninety-one most relevant publications are analyzed as qualitative evidence for conceptualizing the constraints. Secondly, the thesis empirically described the adaptations in participatory financing to the constraints, and resulted outcomes. A multiple case-study research is designed using working capital financing (WCF), consumer financing (CF), and commodity operations financing (COF) as the cases. Thirty in-depth interviews are conducted with the Islamic banking personnel dealing in these financings, using snowballing within the cases. Related documents and observations are used too as source of evidence. The data is analyzed through Qualitative Content Analysis (QCA) process within QSR NVivo. The findings are reported as a holistic post-empirical Constraints, Adaptations, and Outcomes (CAO) framework. The CAO framework specify three broad categories of constrains, which are i) uncertainty ii), low demand, and iii) regulatory constraints. The participatory financing has adapted well in terms of i) repositioning to the market, ii) restructuring of its risk management, iii) restructuring the sharing mechanism, and iv) restructuring its operations. As outcomes, i) the repositioning and revised sharing structure has increased the demand of participatory financings, ii) the restructuring of risk management has reduced the uncertainty, andiii) the restructuring of its risk management and operations have made the participatory financing more effective within current regulations. Thus, due to these adaptations the participatory financing has become more viable and has consequently grown significantly in Pakistan. The novel CAO framework provides a base for the theoretical understanding of the current adaptation to constraints within Islamic banking, and specifies its outcomes. Moreover, it can provide bases for policy making to deal with the contemporary and future constraints to Islamic banking to ensure its sustainability and growth.