Flat slabs have been widely used to allow the larger interior areas to be created in architectural plans, reduce the height of the building by allowing more story heights, and save time and money during the manufacturing phase by decreasing the formwork and reinforcing labor. However, the punching mechanism that may occur suddenly and brittle in such slabs creates an important risk that should be considered and avoided during the design phase. Within the scope of this study, the punching behavior of two-way reinforced concrete slabs, with more than one opening with variations in size and position, was examined. In addition, the performance of an innovative strengthening method has been investigated by using anchors in the Textile Reinforced Mortar (TRM) strips to reduce the negative effects of openings on the punching behavior of the slabs. As a result of the experimental study, it was determined that the openings in the slabs negatively affect the punching behavior. Applying the strengthening method reduced these negative effects and increased the punching strength of the reinforced slabs by an average of 67%. The punching capacities of the experimental specimens tested within the horizon of the study were calculated using the equations suggested by Eurocode 2. The obtained results were compared with the experimental results, and the success of Eurocode 2 was evaluated with the experimental variables.