This thesis integrates Lean construction (LC) with the organisational assessment method ofmaturity models (MM) and delivers an original contribution to knowledge in the form of avalidated innovative organisational framework to measure the current state of LC maturity,which is called Lean Construction Maturity Model (LCMM). This framework provides andsupports organisations towards the development of greater maturity and subsequentlyenhances the awareness and understanding of LC. The aim of this research was to enableorganisations to measure the gap between their current state and where they want to be interms of embedding LC. Accordingly, the research addressed this aim further by providingbusinesses with support and guidance in their LC maturation process in particular inmeasuring sought improvement in their journey towards greater maturity in LC. The studywas conducted as a qualitative mixed-method design in order to discover and achieve a richunderstanding of the phenomenon of LC maturity from LC key informants and best fulfil theresearch aim. Consequently, a phenomenological approach was utilised, with focus groups(FGs) as the primary study, combined with a group interview as well as individual interviewsas supplementary components. To ensure validity, three different approaches weredeployed: first the triangulation of three different methods to collect the data, second a richand thick-description, and finally the validation of the developed framework by memberchecks in the form of interviews and a FG. The major findings of this research are: thesuccessful integration of MMs and LC achieved through the development of the proposedframework, and the simplification of LC into 11 Key Attributes that explain LC in a simplerand better way than before. This framework defined a LC maturity assessment methodutilising five maturity levels, 11 Key Attributes, which have been described through 60Behaviours, Goals & Practices, and 75 Ideal Statements that more mature organisations willexemplify. Finally, the most important consequence of this work is the enabling oforganisations to obtain a systemic and holistic overview of their current state of LC maturityand providing them with support in their maturation