Many antiparasitic drugs have become obsolete and ineffective in treating parasitic diseases. This ineffectiveness arises from parasite drug resistance, high toxicity, and low drug efficacy. Thus, the discovery of novel agents is urgently needed to control parasitic diseases. Various strategies are employed in drug discovery, design, and development. This review highlights the paradigm of searching for bioactive molecules produced during inter- and intraspecific competition among organisms, particularly between microbes and parasites, as a strategy for antiparasitic drug discovery. Competitive interactions occur when individuals of the same or different species coexist in overlapping niches and compete for space and resources. These interactions are well recognized. Therefore, bioactive molecules released during these interactions are promising targets for novel drug discovery. Compelling data indicate that microbes remain a potential source for the discovery of novel antiparasitic drugs because of their diversity. Many antimicrobial producers in nature have yet to be isolated and investigated. This body of evidence underscores the success of numerous therapeutic drugs, including penicillin, β-lactams, and tetracyclines, which have been successfully discovered and developed for treating infectious diseases. This review comprehensively covers these concepts, with a particular focus on inter- and intraspecific competition in the discovery of novel antiparasitic agents. This approach will pave the way for identifying alternative strategies to control and eradicate parasitic diseases that continue to threaten human health. Additionally, this review discusses current antiparasitic drugs and their mechanisms of action, limitations, and existing gaps. This discussion emphasizes the ongoing need to explore novel antiparasitic drugs.