The post-weaning period is a critical period for pigs and is often associated with reduced feed intake, impaired gut health, and reduced growth performance. Pharmacological concentrations of zinc oxide have been widely used in nursery diets to alleviate these challenges, but increasing environmental and regulatory concerns have encouraged the evaluation of alternative nutritional strategies. Dietary acidifiers have been shown to reduce gastrointestinal pH, limit the proliferation of pathogenic bacteria, and support nutrient utilization in young pigs. As a result, novel acidifiers may represent a practical alternative to zinc oxide in diets for weanling pigs. Therefore, the objective of this study was to test the hypothesis that the addition of the acidifier Protacid Soy Plus (PSP; Higienizo, Madrid, Spain) to diets for weanling pigs would increase growth performance.