diff --git a/janus_core/helpers/janus_types.py b/janus_core/helpers/janus_types.py
index aa92a61f..3fec759a 100644
--- a/janus_core/helpers/janus_types.py
+++ b/janus_core/helpers/janus_types.py
@@ -125,6 +125,7 @@ class CorrelationKwargs(TypedDict, total=True):
     "nequip",
     "dpa3",
     "orb",
+    "mattersim",
 ]
 Devices = Literal["cpu", "cuda", "mps", "xpu"]
 Ensembles = Literal["nph", "npt", "nve", "nvt", "nvt-nh", "nvt-csvr", "npt-mtk"]
diff --git a/janus_core/helpers/mlip_calculators.py b/janus_core/helpers/mlip_calculators.py
index 8b67e8e9..2fff9a2b 100644
--- a/janus_core/helpers/mlip_calculators.py
+++ b/janus_core/helpers/mlip_calculators.py
@@ -284,6 +284,17 @@ def choose_calculator(
 
         calculator = ORBCalculator(model=model, device=device, **kwargs)
 
+    elif arch == "mattersim":
+        from mattersim import __version__
+        from mattersim.forcefield import MatterSimCalculator
+
+        if isinstance(model_path, Path):
+            model_path = str(model_path)
+        elif not isinstance(model_path, str):
+            model_path = "mattersim-v1.0.0-5M"
+
+        calculator = MatterSimCalculator(load_path=model_path, device=device, **kwargs)
+
     else:
         raise ValueError(
             f"Unrecognized {arch=}. Suported architectures "
diff --git a/pyproject.toml b/pyproject.toml
index 8b2f208f..b2f4cf4e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -60,6 +60,9 @@ orb = [
 sevennet = [
     "sevenn == 0.10.3",
 ]
+mattersim = [
+    "mattersim == 1.1.1",
+]
 all = [
     "janus-core[chgnet]",
     "janus-core[dpa3]",
@@ -67,6 +70,7 @@ all = [
     "janus-core[nequip]",
     "janus-core[orb]",
     "janus-core[sevennet]",
+      "janus-core[mattersim]",
 ]
 
 # MLIPs with dgl dependency
diff --git a/tests/test_mlip_calculators.py b/tests/test_mlip_calculators.py
index 693efde2..6b44a55f 100644
--- a/tests/test_mlip_calculators.py
+++ b/tests/test_mlip_calculators.py
@@ -74,6 +74,7 @@
         ("chgnet", "cpu", {"model": CHGNET_MODEL}),
         ("dpa3", "cpu", {"model_path": DPA3_PATH}),
         ("dpa3", "cpu", {"model": DPA3_PATH}),
+        ("mattersim", "cpu", {}),
         ("nequip", "cpu", {"model_path": NEQUIP_PATH}),
         ("nequip", "cpu", {"model": NEQUIP_PATH}),
         ("orb", "cpu", {}),
diff --git a/tests/test_single_point.py b/tests/test_single_point.py
index cca0a0c7..975a5c18 100644
--- a/tests/test_single_point.py
+++ b/tests/test_single_point.py
@@ -70,6 +70,7 @@ def test_potential_energy(
     [
         ("chgnet", "cpu", -29.331436157226562, "NaCl.cif", {}),
         ("dpa3", "cpu", -27.053507387638092, "NaCl.cif", {"model_path": DPA3_PATH}),
+        ("mattersim", "cpu", -27.06208038330078, "NaCl.cif", {}),
         (
             "nequip",
             "cpu",