The research in this thesis focused on organisations that can contribute to increased sustainability development in urban freight transport activities. In this study, these organisations were identified, studied, grouped together and labelled as influencing organisations. Four types of influencing organisations in urban freight transport were identified: Business Improvement Districts (BIDs), facility management companies, property owners and public procurement organisations. The results indicated that influencing organisations use a variety of measures and engage in a wide range of urban freight transport initiatives. The way that they engage depends on the types of organisations involved and the relationships the influencers had with said organisations. The findings suggest that influencing organisations have certain characteristics, including: i) the ability to unite other actors, notably goods receivers (such as shops, offices, hotels, restaurants), ii) high motivation to engage in urban freight transport-related questions and sustainability, iii) possessing effective tools to promote sustainable measures, such as the capability to orchestrate and consolidate physical flows, leverage based on contractual relationships, administrative power, outreach power and serving as a common voice for establishments. This places them in a strong position to support the upscaling of sustainable urban freight transport initiatives and broaden the level of implementation. This study paid attention to actors beyond those that are directly associated with urban freight supply chains (carriers, shippers, goods receivers and regulators) to increase the understanding of the role of these organisations in promoting sustainability improvements in urban freight transport activities. The in-depth analysis of the activities carried out by influencing organisations shows why it is important to include them within the scope of urban freight measures and policies: i) they help to overcome the inertia inhibiting the implementation of sustainable urban freight transport initiatives, and ii) they have a connection to many goods receivers as well as the leverage to influence and possibly unite them. Moreover, influencers often have available resources to invest in new infrastructural solutions or processes and the motivation and incentives to carry out these initiatives, thus allowing this engagement to be beneficial both for them and the sustainable development of cities. The results of this thesis provide insights for policymakers about forming policies and regulations to stimulate the engagement of influencers in urban freight transport. This research illustrates to the influencing organisations themselves that they can play a valuable role in the future trajectory of urban freight transport development, as well as examples of ways to change urban freight transport to be more sustainable.