Early on, the anti-colonial organisations from Portuguese colonies made diplomatic offensives towards foreign entities such as governments, international organisations, non-state actors, and individual activists to amass support. New York, the headquarters of the United Nations (UN), was instrumental for the anti-colonial organisations intent to isolate Portugal internationally and develop relationships with a broad array of groups. The city was also the headquarters of the American Committee of Africa (ACOA), an organisation that sought to influence the debate on Portuguese colonialism as well as to provide humanitarian aid for the anti-colonial struggle. In addition, individual activists living in the city engaged with anti-colonial organisations, supporting their struggle in myriad ways. This chapter explores New York as an urban space of transnational activism against Portuguese colonialism, highlighting the UN activities, ACOA solidarity, and Robert van Lierop’s actions. It will argue that New York was at a crossroads of a dense web of connections, helping to create formal and informal networks of solidarity with the struggle to end Portuguese colonialism.