diff --git a/mjx/mujoco/mjx/_src/solver.py b/mjx/mujoco/mjx/_src/solver.py
index f57dbd1cce..34dbfec683 100644
--- a/mjx/mujoco/mjx/_src/solver.py
+++ b/mjx/mujoco/mjx/_src/solver.py
@@ -598,6 +598,19 @@ def body(ctx: Context) -> Context:
   ctx = Context.create(m, d)
   if m.opt.iterations == 1:
     ctx = body(ctx)
+
+  elif hasattr(m.opt, 'fixed_iterations') and m.opt.fixed_iterations is not None:
+  # Use fori_loop with static bounds for gradient compatibility
+   def fixed_body_fn(i, ctx):
+    return body(ctx)
+  
+  # This loop runs exactly fixed_iterations times
+   ctx = jax.lax.fori_loop(
+      0, m.opt.fixed_iterations,
+      fixed_body_fn,
+      ctx
+  )  
+    
   else:
     ctx = jax.lax.while_loop(cond, body, ctx)
 
diff --git a/mjx/mujoco/mjx/_src/solver_test.py b/mjx/mujoco/mjx/_src/solver_test.py
index 0b1b3b5a07..3c89ab5e56 100644
--- a/mjx/mujoco/mjx/_src/solver_test.py
+++ b/mjx/mujoco/mjx/_src/solver_test.py
@@ -25,6 +25,7 @@
 import numpy as np
 
 
+
 # tolerance for difference between MuJoCo and MJX solver calculations,
 # mostly due to float precision
 _TOLERANCE = 5e-3
diff --git a/mjx/mujoco/mjx/_src/types.py b/mjx/mujoco/mjx/_src/types.py
index 8d9ade1849..762c30969f 100644
--- a/mjx/mujoco/mjx/_src/types.py
+++ b/mjx/mujoco/mjx/_src/types.py
@@ -18,6 +18,7 @@
 from typing import Tuple, Union
 import warnings
 
+from typing import Optional
 import jax
 import mujoco
 from mujoco.mjx._src.dataclasses import PyTreeNode  # pylint: disable=g-importing-member
@@ -483,6 +484,7 @@ class OptionJAX(PyTreeNode):
   disableactuator: int
   sdf_initpoints: int
   has_fluid_params: bool
+  fixed_iterations: Optional[int] = None 
 
 
 class OptionC(PyTreeNode):