Scientific practices stemming from colonialism, whereby middle- and low-income countries supply data for high-income countries and the contributions of local expertise are devalued, are still prevalent today in the field of palaeontology. In response to these unjust practices, countries such as Mexico and Brazil adopted protective laws and regulations during the twentieth century to preserve their palaeontological heritage. However, scientific colonialism is still reflected in many publications describing fossil specimens recovered from these countries. Here, we present examples of ‘palaeontological colonialism’ from publications on Jurassic–Cretaceous fossils from NE Mexico and NE Brazil spanning the last three decades. Common issues that we identified in these publications are the absence of both fieldwork and export permit declarations and the lack of local experts among authorships. In Mexico, access to many fossil specimens is restricted on account of these specimens being housed in private collections, whereas a high number of studies on Brazilian fossils are based on specimens illegally reposited in foreign collections, particularly in Germany and Japan. Finally, we outline and discuss the wider academic and social impacts of these research practices, and propose exhaustive recommendations to scientists, journals, museums, research institutions and government and funding agencies in order to overcome these practices. Files included: Table S1. Sabinas, La Popa and Parras basins fossil publications by foreign authors Table S2. Araripe fossil publications by foreign authors (vertebrates and plants) Table S3. Preliminary list of Araripe fossil arthropod publications Table S4. List of palaeontology museums and postgraduate courses in Brazil with palaeontology advisors Table S5. List of palaeontology museums and postgraduate courses in Mexico with palaeontology advisors Translation S1. Complete article in Portuguese Translation S2. Complete article in Spanish Appendix A. Laws in Brazil (includes English translations) Appendix B. Laws in Mexico (includes English translations)