The European Structural and Investment Funds (ESIF) are the main instrument of the European Union (EU) Cohesion Policy to promote convergence, economic growth and reduce imbalances between EU members. The objectives of the 2014–2020 programming period follow the agenda of the Europe 2020 Strategy to promote smart, sustainable and inclusive growth of EU members. Since before joining the EU, in 1986, until the end of the Portugal 2020 Partnership Agreement (PT2020), Portugal will have received more than EUR 130 billion. Have the subsidies that Portugal has received been well applied? Our study fills a gap in the literature by portraying citizens’ perceptions about the effectiveness of EU funds for the development of the country and its regions. The study is quantitative in nature, and a non-probabilistic sample of 1119 participants answered our survey. A high proportion (76%) of the respondents considered that EU funds contributed to the development of the region where they live, although a significant percentage of the respondents (more than half) considered that there may be corruption in Portugal. The Portuguese also mentioned the existence of practices such as favouritism and lobbying regarding the approval of projects. Our findings are supported by the literature, which refers to “lost opportunities” in the inefficient application of ESIF, while recognising that EU funds have played a significant role in Portugal’s development over the last three decades.