The United Kingdom has played a prominent role in the Common Fisheries Policy—by contributing to fisheries activities and also by participating in the design of the fisheries policy. Brexit is certain to have significant repercussions for European fisheries activities and their management. This study analyses the views held by companies linked to the fisheries sector in Galicia (fishing, wholesale trade, canned fish, aquaculture, and fish processing), one of the European regions most affected by Brexit given that more than 80% of the Spanish fishing fleet working on UK waters is located in this region. We adopt a quantitative methodology based on the Pearson’s chi-squared test, the likelihood ratio, and the Fisher’s exact test for analyzing opinions about various topics. Results indicate that companies engaged in marine fisheries or trade in fishing goods hold a mostly negative view of Brexit’s effects. In total, 30% of those surveyed anticipate that Brexit will have negative consequences for EU workers in UK fishery companies; a slightly higher percentage of these respondents expect the United Kingdom’s exit from the EU to depress Spain’s foreign trade; over half of those surveyed perceived Brexit as resulting in the adverse scenario of reduced access to fisheries’ resources and were in favor of reformulating the current system of total allowable catches (TACs) and quotas among the remaining post-Brexit member states. Most respondents also agreed that Brexit will have negative repercussions on vessels of the Galician fleet operating under the British flag. Our statistical analysis identifies a significant relationship between negative attitudes and the firm’s size for fisheries’ sectors as a whole; however, no relation between those attitudes and firm size or turnover is identified when the particular fishing companies’ perceptions are evaluated.