diff --git a/sympy2jax/__init__.py b/sympy2jax/__init__.py
index 2422095..f271964 100644
--- a/sympy2jax/__init__.py
+++ b/sympy2jax/__init__.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .sympy_module import SymbolicModule
+from .sympy_module import concatenate, stack, SymbolicModule
 
 
 __version__ = "0.0.4"
diff --git a/sympy2jax/sympy_module.py b/sympy2jax/sympy_module.py
index 7ab66fd..6e4dcd5 100644
--- a/sympy2jax/sympy_module.py
+++ b/sympy2jax/sympy_module.py
@@ -26,6 +26,9 @@
 
 PyTree = Any
 
+concatenate = sympy.Function("concatenate")
+stack = sympy.Function("stack")
+
 
 def _reduce(fn):
     def fn_(*args):
@@ -34,7 +37,16 @@ def fn_(*args):
     return fn_
 
 
+def _single_args(fn):
+    def fn_(*args):
+        return fn(args)
+
+    return fn_
+
+
 _lookup = {
+    concatenate: _single_args(jnp.concatenate),
+    stack: _single_args(jnp.stack),
     sympy.Mul: _reduce(jnp.multiply),
     sympy.Add: _reduce(jnp.add),
     sympy.div: jnp.divide,
diff --git a/tests/test_symbolic_module.py b/tests/test_symbolic_module.py
index 7c823ef..70b3608 100644
--- a/tests/test_symbolic_module.py
+++ b/tests/test_symbolic_module.py
@@ -143,3 +143,23 @@ def _get_params(module):
         return {id(x) for x in jax.tree_leaves(module) if eqx.is_array(x)}
 
     assert _get_params(mod).issuperset(_get_params(mlp))
+
+
+def test_concatenate():
+    x, y, z = sympy.symbols("x y z")
+    cat = sympy2jax.concatenate(x, y, z)
+    mod = sympy2jax.SymbolicModule(expressions=cat)
+    assert_equal(
+        mod(x=jnp.array([0.4, 0.5]), y=jnp.array([0.6, 0.7]), z=jnp.array([0.8, 0.9])),
+        jnp.array([0.4, 0.5, 0.6, 0.7, 0.8, 0.9]),
+    )
+
+
+def test_stack():
+    x, y, z = sympy.symbols("x y z")
+    stack = sympy2jax.stack(x, y, z)
+    mod = sympy2jax.SymbolicModule(expressions=stack)
+    assert_equal(
+        mod(x=jnp.array(0.4), y=jnp.array(0.5), z=jnp.array(0.6)),
+        jnp.array([0.4, 0.5, 0.6]),
+    )