**matscipy: Materials Science at the Atomic Scale with Python** **Authors:** Petr Grigorev, Lucas Frérot, Fraser Birks, Adrien Gola, Jacek Golebiowski, Jan Grießer, Johannes L. Hörmann, Andreas Klemenz, Gianpietro Moras, Wolfram G. Nöhring, Jonas A. Oldenstaedt, Punit Patel, Thomas Reichenbach, Thomas Rocke, Lakshmi Shenoy, Michael Walter, Simon Wengert, Lei Zhang, James R. Kermode, and Lars Pastewka **Journal:** Journal of Open Source Software, 9(93), 5668 **DOI:** 10.21105/joss.05668 **License:** Creative Commons Attribution 4.0 International License (CC BY 4.0) **Summary:** matscipy is a Python package designed for atomic-scale modeling in materials science. It provides tools for simulating and analyzing materials at the atomic level, focusing on multiscale approaches that bridge the gap between atomic and continuum scales. The package supports various applications, including elasticity, plasticity, fracture mechanics, tribology, and electrochemistry. It includes functionalities for generating initial atomic configurations, analyzing dynamical simulations, and connecting atomic systems to continuum descriptions. matscipy also offers general utility functions such as neighbor lists, atomic strain calculations, and radial, spatial, and angular correlation functions. The package aims to facilitate multi-scale coupling and is compatible with widely used simulation codes like ASE, providing a flexible and efficient framework for materials science research. **Keywords:** materials science, atomic-scale modeling, Python, multiscale modeling, elasticity, plasticity, fracture mechanics, tribology, electrochemistry.**matscipy: Materials Science at the Atomic Scale with Python** **Authors:** Petr Grigorev, Lucas Frérot, Fraser Birks, Adrien Gola, Jacek Golebiowski, Jan Grießer, Johannes L. Hörmann, Andreas Klemenz, Gianpietro Moras, Wolfram G. Nöhring, Jonas A. Oldenstaedt, Punit Patel, Thomas Reichenbach, Thomas Rocke, Lakshmi Shenoy, Michael Walter, Simon Wengert, Lei Zhang, James R. Kermode, and Lars Pastewka **Journal:** Journal of Open Source Software, 9(93), 5668 **DOI:** 10.21105/joss.05668 **License:** Creative Commons Attribution 4.0 International License (CC BY 4.0) **Summary:** matscipy is a Python package designed for atomic-scale modeling in materials science. It provides tools for simulating and analyzing materials at the atomic level, focusing on multiscale approaches that bridge the gap between atomic and continuum scales. The package supports various applications, including elasticity, plasticity, fracture mechanics, tribology, and electrochemistry. It includes functionalities for generating initial atomic configurations, analyzing dynamical simulations, and connecting atomic systems to continuum descriptions. matscipy also offers general utility functions such as neighbor lists, atomic strain calculations, and radial, spatial, and angular correlation functions. The package aims to facilitate multi-scale coupling and is compatible with widely used simulation codes like ASE, providing a flexible and efficient framework for materials science research. **Keywords:** materials science, atomic-scale modeling, Python, multiscale modeling, elasticity, plasticity, fracture mechanics, tribology, electrochemistry.