This study employs instrumented indentation testing (IIT) in combination with finite element modeling (FEM) to analyze the mechanical behavior and deformation processes of an aluminum AA 3003-H14 sheet. IIT, commonly known as nanoindentation or depth-sensing indentation, is an effective method for evaluating the mechanical properties of materials such as thin films, coatings, and bulk materials at very small scales. In this approach, the load-displacement curve obtained from nanoindentation provides insight into the stress-strain characteristics of an elastic-plastic material. However, establishing an analytical relationship between these parameters is complex due to the localized stress fields generated during indentation. This work implements a combined experimental and numerical approach to understand the material deformation under the localized stress conditions induced by a nano indenter probe pressing into the material’s surface. The experimental component of this study involves measuring nanoindentation responses of the sheet surface by using a three-sided diamond pyramid Berkovich indenter. By measuring the load and displacement during the indentation process, critical mechanical properties, such as yield strength, hardness, and elastic modulus are estimated at the nanoscale level. This method provides valuable information about how the material behaves under concentrated stress and allows for the assessment of its elastic and plastic properties. The numerical approach involves finite element (FE) simulations of the IIT experiments to provide computational validation of the load-displacement responses observed experimentally. These simulations are performed using both axisymmetric and three-dimensional (3D) models. The axisymmetric model assumes symmetrical loading conditions and is employed for efficient computation to provide prompt insights into the overall material response to indentation. This model is useful for preliminary analysis and parameter identification and optimization. The 3D model, however, offers a more detailed view of material behavior during indentation, capturing the localized stress and strain fields with greater accuracy. This thorough analysis is essential for refining the understanding of the deformation mechanisms within the aluminum alloy when subjected to nanoindentation. By comparing the load-displacement responses predicted through FEM with those obtained experimentally, the fidelity and the accuracy of the FE models are established. This IIT-FEM approach offers a robust framework for analyzing material deformation and properties at small scales, aiding in the optimization of manufacturing processes and components requiring accurate mechanical characterization.