Construction　industry　significantly　contributes　to　New　Zealand＇s　economic　development.　However,　the　delivery　of　construction　projects　is　usually　plagued　by　cost　overruns,　which　turn　potentially　successful　projects　into　money-losing　ventures,　resulting　in　various　other　unexpected　negative　impacts.　The　objectives　of　the　study　were　to　identify,　classify,　and　assess　the　impacts　of　the　factors　affecting　project　cost　in　New　Zealand.　The　proposed　research　model　was　examined　with　structural　equation　modelling.　Recognising　the　lack　of　a　systematic　approach　for　assessing　the　influencing　factors　associated　with　project　cost,　this　study　identified　30　influencing　factors　from　various　sources　and　quantified　their　relative　impacts.　The　research　data　were　gathered　through　a　questionnaire　survey　circulated　across　New　Zealand　construction　industry.　A　total　of　283　responses　were　received,　with　a　37%　response　rate.　A　model　was　developed　for　testing　the　relationship　between　project　cost　and　the　influential　factors.　The　proposed　research　model　was　examined　with　structural　equation　modelling　(SEM).　According　to　the　results　of　the　analysis,　market　and　industry　conditions　factor　has　the　most　significant　effect　on　project　cost,　while　regulatory　regime　is　the　second-most　significant　influencing　factor,　followed　by　key　stakeholders＇　perspectives.　The　findings　can　improve　project　cost　performance　through　the　identification　and　evaluation　of　the　cost-influencing　factors.　The　results　of　such　analysis　enable　industry　professionals　to　better　understand　cost-related　risks　in　the　complex　environment.