The purpose of this study is to compare the environmental sustainability and nutrient densities of various plant-based drinks from soy, oat, almond, rice, spelt, and cashew against cow’s milk from different production systems (i.e., grass-fed, pasture-raised, and arable-land based). For the nutritional assessment, we developed the Food Substitution Index 20 to rank the substitution potential of plant-based drink for cow’s milk. This nutrient algorithm is characterized by micronutrient deficiencies that exist in a specific dietary pattern. In addition to essential nutrients, we also included an analysis of amino acids, fatty acids, and disqualifying nutrients. For the environmental assessment, we performed a life cycle assessment to calculate cradle to factory gate impacts per one serving size of drink for seven impact categories; namely, global warming potential, deforestation, water scarcity, acidification, particulate matter, eutrophication, soil quality, and non-renewable energy use. Finally, we measured environmental impacts against the aforementioned nutrient density algorithm to calculate nutritionally-invested environmental impacts. Overall, plant-based drinks are environmentally favorable when compared to cow’s milk but while these drinks may have lower climate impacts they can have higher impacts than cow’s milk in other environmental categories such as deforestation or water scarcity, which underscores the importance of considering multiple impacts to avoid burden shifting. When the nutritional dimension is introduced, only soy drink systematically outperforms cow’s milk, which complicates setting recommendations. Moreover, plant-based drinks must be fortified to compete with cow’s milk on a micronutrient basis whereas for the other nutrition categories (e.g., fatty acids) there are tradeoffs across animal and plant drinks.