The spread of both microplastics and antibiotics is a growing concern in part because of their effect on the bacteria that encounter these pollutants. Both individually and combined, microplastics and antibiotics increase antibiotic resistance in bacterial populations. The full effect and mechanisms of how microplastics increase resistance is still being researched. In this review, we gathered data from a variety of published studies to find the most probable reasons microplastics are increasing antibiotic resistance. Due to the immense variety in microplastics, there is no one distinct answer. Often, microplastic properties allow for the adsorption of antibiotics and/or attraction of bacteria. The concentrations of the antibiotics adsorbed are non-lethal, which may cause the bacteria to exhibit a stress response, such as the SOS response. This could cause mutations that create antibiotic resistance genes within the bacteria’s genome. Attracted bacteria often form biofilms on microplastics' surfaces, and some studies suggest that microplastics even naturally select for bacteria that form strong biofilms. Biofilms have previously been shown to increase antibiotic resistance of bacteria through their own structure and through the increased amount of horizontal gene transfer that biofilms encourage. Despite multiple possibilities on how, microplastics increase antibiotic resistance. A consequence of microplastics and antibiotics in our environment could be reduced antibiotic effectiveness for medical treatments. Further studies are needed to determine how bacterial colonization of microplastics affects the human body when consumed.