Mycotoxins are secondary metabolites originating from several species of fungi that have proven to demonstrate high toxicity. In addition, potential contamination sources can promote increased human exposure to the adverse effects of these toxins. For this reason, it was necessary to develop several analytical methods that allow detection with the highest possible sensitivity for these toxic metabolites. Furthermore, since these methods involve high cost, are lengthy, and have sensitivity requirements, the development of multi-analyte detection methods is indispensable. The increasing consumption of groundnuts (legumes) as well as nuts (such as almonds, walnuts, and pistachios) and dried fruit (raisins and dried figs) has increased the risk of poisoning and the harmful effects of mycotoxins, which has encouraged studies for the creation of these methods. This review addresses the most representative methods applied to analyze and quantify mycotoxins in groundnuts (peanuts) together with decontamination techniques. The methodologies presented in this review are primarily based on analytical techniques for nuts and dried fruits. However, each of these methodologies can also be applied to peanut analysis for comparison and use. It is also relevant to highlight the importance of the development of multi-analyte methods in order to identify multiple mycotoxins using a single method, saving time, costs, and resources.