diff --git a/doc/changelog.rst b/doc/changelog.rst
index 34b2cf16..0e7576a2 100644
--- a/doc/changelog.rst
+++ b/doc/changelog.rst
@@ -1030,7 +1030,7 @@ General
      become the default integrator in a future version.
 
    The table below shows the compute cost of the 627-DoF `humanoid100
-   <https://github.com/google-deepmind/mujoco/blob/main/model/humanoid100/humanoid100.xml>`__ model using different
+   <https://github.com/google-deepmind/mujoco/blob/main/model/humanoid/humanoid100.xml>`__ model using different
    integrators. "implicit (old)" uses dense RNE derivatives, "implicit (new)" is after the sparsification mentioned
    above. Timings were measured on a single core of an AMD 3995WX CPU.
 
@@ -1057,7 +1057,7 @@ General
    duplicated in order to circumvent this limitation as they previously were.
 #. The non-zeros for the sparse constraint Jacobian matrix are now precounted and used for matrix memory allocation.
    For instance, the constraint Jacobian matrix from the `humanoid100
-   <https://github.com/google-deepmind/mujoco/blob/main/model/humanoid100/humanoid100.xml>`__ model, which previously
+   <https://github.com/google-deepmind/mujoco/blob/main/model/humanoid/humanoid100.xml>`__ model, which previously
    required ~500,000 ``mjtNum``'s, now only requires ~6000. Very large models can now load and run with the CG solver.
 #. Modified :ref:`mju_error` and :ref:`mju_warning` to be variadic functions (support for printf-like arguments). The
    functions :ref:`mju_error_i`, :ref:`mju_error_s`, :ref:`mju_warning_i`, and :ref:`mju_warning_s` are now deprecated.
@@ -1105,7 +1105,7 @@ General
 
 1. A more performant mju_transposeSparse has been implemented that doesn't require dense memory allocation.
    For a constraint Jacobian matrix from the
-   `humanoid100.xml <https://github.com/google-deepmind/mujoco/blob/main/model/humanoid100/humanoid100.xml>`__ model,
+   `humanoid100.xml <https://github.com/google-deepmind/mujoco/blob/main/model/humanoid/humanoid100.xml>`__ model,
    this function is 35% faster.
 #. The function :ref:`mj_name2id` is now implemented using a hash function instead of a linear search for better
    performance.
diff --git a/model/humanoid100/humanoid100.xml b/model/humanoid/humanoid100.xml
similarity index 88%
rename from model/humanoid100/humanoid100.xml
rename to model/humanoid/humanoid100.xml
index 3279e85c..e7fef05b 100644
--- a/model/humanoid100/humanoid100.xml
+++ b/model/humanoid/humanoid100.xml
@@ -19,8 +19,6 @@
 
      Humanoid and 100 free primitive objects.
 -->
-  <include file="humanoid_body.xml"/>
-
   <option timestep="0.005"/>
 
   <size memory="100M"/>
@@ -51,18 +49,16 @@
   </default>
 
   <asset>
+    <model file="humanoid.xml"/>
     <texture type="skybox" builtin="gradient" width="512" height="512" rgb1=".4 .6 .8" rgb2="0 0 0"/>
-    <texture name="texgeom" type="cube" builtin="flat" mark="cross" width="128" height="128"
-             rgb1="0.6 0.6 0.6" rgb2="0.6 0.6 0.6" markrgb="1 1 1"/>
-    <texture name="texplane" type="2d" builtin="checker" rgb1=".4 .4 .4" rgb2=".6 .6 .6"
-             width="512" height="512"/>
-    <material name="MatPlane" reflectance="0.3" texture="texplane" texrepeat="1 1" texuniform="true"
-              rgba=".7 .7 .7 1"/>
-    <material name="capsule" texture="texgeom" texuniform="true" rgba=".4 .9 .6 1" />
-    <material name="ellipsoid" texture="texgeom" texuniform="true" rgba=".4 .6 .9 1" />
-    <material name="box" texture="texgeom" texuniform="true" rgba=".4 .9 .9 1" />
-    <material name="cylinder" texture="texgeom" texuniform="true" rgba=".8 .6 .8 1" />
-    <material name="sphere" texture="texgeom" texuniform="true" rgba=".9 .1 .1 1" />
+    <texture name="texgeom" type="cube" builtin="flat" mark="cross" width="128" height="128" rgb1="0.6 0.6 0.6" rgb2="0.6 0.6 0.6" markrgb="1 1 1"/>
+    <texture name="texplane" type="2d" builtin="checker" rgb1=".4 .4 .4" rgb2=".6 .6 .6" width="512" height="512"/>
+    <material name="MatPlane" reflectance="0.3" texture="texplane" texrepeat="1 1" texuniform="true" rgba=".7 .7 .7 1"/>
+    <material name="capsule" texture="texgeom" texuniform="true" rgba=".4 .9 .6 1"/>
+    <material name="ellipsoid" texture="texgeom" texuniform="true" rgba=".4 .6 .9 1"/>
+    <material name="box" texture="texgeom" texuniform="true" rgba=".4 .9 .9 1"/>
+    <material name="cylinder" texture="texgeom" texuniform="true" rgba=".8 .6 .8 1"/>
+    <material name="sphere" texture="texgeom" texuniform="true" rgba=".9 .1 .1 1"/>
   </asset>
 
   <visual>
@@ -73,12 +69,13 @@
   <statistic extent="4"/>
 
   <worldbody>
+    <attach model="Humanoid" body="torso" prefix="humanoid_"/>
     <light directional="true" diffuse=".8 .8 .8" pos="0 0 10" dir="0 0 -10"/>
     <geom name="floor" type="plane" size="3 3 .5" material="MatPlane"/>
-    <geom class="border" fromto="-3 3 0 3 3 0"  />
-    <geom class="border" fromto="-3 -3 0 3 -3 0"  />
-    <geom class="border" fromto="3 3 0 3 -3 0"  />
-    <geom class="border" fromto="-3 3 0 -3 -3 0"  />
+    <geom class="border" fromto="-3 3 0 3 3 0"/>
+    <geom class="border" fromto="-3 -3 0 3 -3 0"/>
+    <geom class="border" fromto="3 3 0 3 -3 0"/>
+    <geom class="border" fromto="-3 3 0 -3 -3 0"/>
     <geom class="borderpost" pos="3 3 0"/>
     <geom class="borderpost" pos="-3 3 0"/>
     <geom class="borderpost" pos="3 -3 0"/>
diff --git a/model/humanoid100/humanoid_body.xml b/model/humanoid100/humanoid_body.xml
deleted file mode 100644
index 3dc48b96..00000000
--- a/model/humanoid100/humanoid_body.xml
+++ /dev/null
@@ -1,158 +0,0 @@
-<!-- Copyright 2021 DeepMind Technologies Limited
-     Licensed under the Apache License, Version 2.0 (the "License");
-     you may not use this file except in compliance with the License.
-     You may obtain a copy of the License at
-         http://www.apache.org/licenses/LICENSE-2.0
-     Unless required by applicable law or agreed to in writing, software
-     distributed under the License is distributed on an "AS IS" BASIS,
-     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-     See the License for the specific language governing permissions and
-     limitations under the License.
--->
-
-<mujoco model="Humanoid body">
-<!-- Degree of Freedom: 27
-     Actuators: 21
-
-     This simplified humanoid model, introduced in [1], is designed for bipedal locomotion
-     behaviours. While several variants of it exist in the wild, this version is based on the model
-     in the DeepMind Control Suite [2], which has fairly realistic actuator gains.
-     [1] Synthesis and Stabilization of Complex Behaviors through Online Trajectory Optimization.
-           https://doi.org/10.1109/IROS.2012.6386025
-     [2] DeepMind Control Suite, Tassa et al. https://arxiv.org/abs/1801.00690
--->
-
-  <asset>
-    <texture type="skybox" builtin="gradient" rgb1=".3 .5 .7" rgb2="0 0 0" width="512" height="512"/>
-    <texture name="body" type="cube" builtin="flat" mark="cross" width="128" height="128"
-             rgb1="0.8 0.6 0.4" rgb2="0.8 0.6 0.4" markrgb="1 1 1"/>
-    <material name="body" texture="body" texuniform="true" rgba="0.8 0.6 .4 1"/>
-    <texture name="grid" type="2d" builtin="checker" width="512" height="512" rgb1=".1 .2 .3" rgb2=".2 .3 .4"/>
-    <material name="grid" texture="grid" texrepeat="1 1" texuniform="true" reflectance=".2"/>
-  </asset>
-
-  <default>
-    <motor ctrlrange="-1 1" ctrllimited="true"/>
-    <default class="body">
-      <geom type="capsule" condim="1" friction=".7" solimp=".9 .99 .003" solref=".015 1" material="body"/>
-      <joint type="hinge" damping=".2" stiffness="1" armature=".01" limited="true" solimplimit="0 .99 .01"/>
-      <default class="big_joint">
-        <joint damping="5" stiffness="10"/>
-        <default class="big_stiff_joint">
-          <joint stiffness="20"/>
-        </default>
-      </default>
-    </default>
-  </default>
-
-  <visual>
-    <map force="0.1" zfar="30"/>
-    <rgba haze="0.15 0.25 0.35 1"/>
-    <quality shadowsize="4096"/>
-    <global offwidth="800" offheight="800"/>
-  </visual>
-
-  <worldbody>
-    <body name="torso" pos="0 0 1.5" childclass="body">
-      <light name="top" pos="0 0 2" mode="trackcom"/>
-      <camera name="back" pos="-3 0 1" xyaxes="0 -1 0 1 0 2" mode="trackcom"/>
-      <camera name="side" pos="0 -3 1" xyaxes="1 0 0 0 1 2" mode="trackcom"/>
-      <freejoint name="root"/>
-      <geom name="torso" fromto="0 -.07 0 0 .07 0" size=".07"/>
-      <geom name="upper_waist" fromto="-.01 -.06 -.12 -.01 .06 -.12" size=".06"/>
-      <body name="head" pos="0 0 .19">
-        <geom name="head" type="sphere" size=".09"/>
-        <camera name="egocentric" pos=".09 0 0" xyaxes="0 -1 0 .1 0 1" fovy="80"/>
-      </body>
-      <body name="lower_waist" pos="-.01 0 -.26">
-        <geom name="lower_waist" fromto="0 -.06 0 0 .06 0" size=".06"/>
-        <joint name="abdomen_z" pos="0 0 .065" axis="0 0 1" range="-45 45" class="big_stiff_joint"/>
-        <joint name="abdomen_y" pos="0 0 .065" axis="0 1 0" range="-75 30" class="big_joint"/>
-        <body name="pelvis" pos="0 0 -.165">
-          <joint name="abdomen_x" pos="0 0 .1" axis="1 0 0" range="-35 35" class="big_joint"/>
-          <geom name="butt" fromto="-.02 -.07 0 -.02 .07 0" size=".09"/>
-          <body name="right_thigh" pos="0 -.1 -.04">
-            <joint name="right_hip_x" axis="1 0 0" range="-25 5" class="big_joint"/>
-            <joint name="right_hip_z" axis="0 0 1" range="-60 35" class="big_joint"/>
-            <joint name="right_hip_y" axis="0 1 0" range="-110 20" class="big_stiff_joint"/>
-            <geom name="right_thigh" fromto="0 0 0 0 .01 -.34" size=".06"/>
-            <body name="right_shin" pos="0 .01 -.403">
-              <joint name="right_knee" pos="0 0 .02" axis="0 -1 0" range="-160 2"/>
-              <geom name="right_shin" fromto="0 0 0 0 0 -.3"  size=".049"/>
-              <body name="right_foot" pos="0 0 -.39">
-                <joint name="right_ankle_y" pos="0 0 .08" axis="0 1 0" range="-50 50" stiffness="6"/>
-                <joint name="right_ankle_x" pos="0 0 .04" axis="1 0 .5" range="-50 50" stiffness="3"/>
-                <geom name="right_right_foot" fromto="-.07 -.02 0 .14 -.04 0" size=".027"/>
-                <geom name="left_right_foot" fromto="-.07 0 0 .14  .02 0" size=".027"/>
-              </body>
-            </body>
-          </body>
-          <body name="left_thigh" pos="0 .1 -.04">
-            <joint name="left_hip_x" axis="-1 0 0" range="-25 5" class="big_joint"/>
-            <joint name="left_hip_z" axis="0 0 -1" range="-60 35" class="big_joint"/>
-            <joint name="left_hip_y" axis="0 1 0" range="-110 20" class="big_stiff_joint"/>
-            <geom name="left_thigh" fromto="0 0 0 0 -.01 -.34" size=".06"/>
-            <body name="left_shin" pos="0 -.01 -.403">
-              <joint name="left_knee" pos="0 0 .02" axis="0 -1 0" range="-160 2"/>
-              <geom name="left_shin" fromto="0 0 0 0 0 -.3"  size=".049"/>
-              <body name="left_foot" pos="0 0 -.39">
-                <joint name="left_ankle_y" pos="0 0 .08" axis="0 1 0" range="-50 50" stiffness="6"/>
-                <joint name="left_ankle_x" pos="0 0 .04" axis="1 0 .5" range="-50 50" stiffness="3"/>
-                <geom name="left_left_foot" fromto="-.07 .02 0 .14 .04 0" size=".027"/>
-                <geom name="right_left_foot" fromto="-.07 0 0 .14 -.02 0" size=".027"/>
-              </body>
-            </body>
-          </body>
-        </body>
-      </body>
-      <body name="right_upper_arm" pos="0 -.17 .06">
-        <joint name="right_shoulder1" axis="2 1 1"  range="-85 60"/>
-        <joint name="right_shoulder2" axis="0 -1 1" range="-85 60"/>
-        <geom name="right_upper_arm" fromto="0 0 0 .16 -.16 -.16" size=".04 .16"/>
-        <body name="right_lower_arm" pos=".18 -.18 -.18">
-          <joint name="right_elbow" axis="0 -1 1" range="-90 50" stiffness="0"/>
-          <geom name="right_lower_arm" fromto=".01 .01 .01 .17 .17 .17" size=".031"/>
-          <body name="right_hand" pos=".18 .18 .18">
-            <geom name="right_hand" type="sphere" size=".04" zaxis="1 1 1"/>
-          </body>
-        </body>
-      </body>
-      <body name="left_upper_arm" pos="0 .17 .06">
-        <joint name="left_shoulder1" axis="2 -1 1" range="-60 85"/>
-        <joint name="left_shoulder2" axis="0 1 1"  range="-60 85"/>
-        <geom name="left_upper_arm" fromto="0 0 0 .16 .16 -.16" size=".04 .16"/>
-        <body name="left_lower_arm" pos=".18 .18 -.18">
-          <joint name="left_elbow" axis="0 -1 -1" range="-90 50" stiffness="0"/>
-          <geom name="left_lower_arm" fromto=".01 -.01 .01 .17 -.17 .17" size=".031"/>
-          <body name="left_hand" pos=".18 -.18 .18">
-            <geom name="left_hand" type="sphere" size=".04" zaxis="1 -1 1"/>
-          </body>
-        </body>
-      </body>
-    </body>
-  </worldbody>
-
-  <actuator>
-    <motor name="abdomen_y"       gear="40"  joint="abdomen_y"/>
-    <motor name="abdomen_z"       gear="40"  joint="abdomen_z"/>
-    <motor name="abdomen_x"       gear="40"  joint="abdomen_x"/>
-    <motor name="right_hip_x"     gear="40"  joint="right_hip_x"/>
-    <motor name="right_hip_z"     gear="40"  joint="right_hip_z"/>
-    <motor name="right_hip_y"     gear="120" joint="right_hip_y"/>
-    <motor name="right_knee"      gear="80"  joint="right_knee"/>
-    <motor name="right_ankle_x"   gear="20"  joint="right_ankle_x"/>
-    <motor name="right_ankle_y"   gear="20"  joint="right_ankle_y"/>
-    <motor name="left_hip_x"      gear="40"  joint="left_hip_x"/>
-    <motor name="left_hip_z"      gear="40"  joint="left_hip_z"/>
-    <motor name="left_hip_y"      gear="120" joint="left_hip_y"/>
-    <motor name="left_knee"       gear="80"  joint="left_knee"/>
-    <motor name="left_ankle_x"    gear="20"  joint="left_ankle_x"/>
-    <motor name="left_ankle_y"    gear="20"  joint="left_ankle_y"/>
-    <motor name="right_shoulder1" gear="20"  joint="right_shoulder1"/>
-    <motor name="right_shoulder2" gear="20"  joint="right_shoulder2"/>
-    <motor name="right_elbow"     gear="40"  joint="right_elbow"/>
-    <motor name="left_shoulder1"  gear="20"  joint="left_shoulder1"/>
-    <motor name="left_shoulder2"  gear="20"  joint="left_shoulder2"/>
-    <motor name="left_elbow"      gear="40"  joint="left_elbow"/>
-  </actuator>
-</mujoco>
diff --git a/test/benchmark/engine_util_sparse_benchmark_test.cc b/test/benchmark/engine_util_sparse_benchmark_test.cc
index 80839276..e3850d07 100644
--- a/test/benchmark/engine_util_sparse_benchmark_test.cc
+++ b/test/benchmark/engine_util_sparse_benchmark_test.cc
@@ -501,7 +501,7 @@ void ABSL_ATTRIBUTE_NO_TAIL_CALL BM_combineSparse_old(
 BENCHMARK(BM_combineSparse_old);
 
 static void BM_transposeSparse(benchmark::State& state, TransposeFuncPtr func) {
-  static mjModel* m = LoadModelFromPath("humanoid100/humanoid100.xml");
+  static mjModel* m = LoadModelFromPath("humanoid/humanoid100.xml");
 
   // force use of sparse matrices
   m->opt.jacobian = mjJAC_SPARSE;
@@ -547,7 +547,7 @@ BM_transposeSparse_old(benchmark::State& state) {
 BENCHMARK(BM_transposeSparse_old);
 
 static void BM_sqrMatTDSparse(benchmark::State& state, SqrMatTDFuncPtr func) {
-  static mjModel* m = LoadModelFromPath("humanoid100/humanoid100.xml");
+  static mjModel* m = LoadModelFromPath("humanoid/humanoid100.xml");
   mjData* d = mj_makeData(m);
 
   // force use of sparse matrices
diff --git a/test/benchmark/parse_benchmark_test.cc b/test/benchmark/parse_benchmark_test.cc
index f74ed03f..c5855865 100644
--- a/test/benchmark/parse_benchmark_test.cc
+++ b/test/benchmark/parse_benchmark_test.cc
@@ -86,7 +86,7 @@ void ABSL_ATTRIBUTE_NO_TAIL_CALL BM_ParseHumanoid(benchmark::State& state) {
 BENCHMARK(BM_ParseHumanoid);
 
 void ABSL_ATTRIBUTE_NO_TAIL_CALL BM_ParseHumanoid100(benchmark::State& state) {
-  run_parse_benchmark(GetModelPath("humanoid100/humanoid100.xml"), state);
+  run_parse_benchmark(GetModelPath("humanoid/humanoid100.xml"), state);
 }
 BENCHMARK(BM_ParseHumanoid100);
 
diff --git a/test/benchmark/step_benchmark_test.cc b/test/benchmark/step_benchmark_test.cc
index dbb98432..0c4c7bca 100644
--- a/test/benchmark/step_benchmark_test.cc
+++ b/test/benchmark/step_benchmark_test.cc
@@ -103,7 +103,7 @@ BENCHMARK(BM_StepHumanoid);
 
 void ABSL_ATTRIBUTE_NO_TAIL_CALL BM_StepHumanoid100(benchmark::State& state) {
   MujocoErrorTestGuard guard;
-  static mjModel* model = LoadModelFromPath("humanoid100/humanoid100.xml");
+  static mjModel* model = LoadModelFromPath("humanoid/humanoid100.xml");
   run_step_benchmark(model, state);
 }
 BENCHMARK(BM_StepHumanoid100);
diff --git a/test/engine/engine_support_test.cc b/test/engine/engine_support_test.cc
index 67e41787..4393f02b 100644
--- a/test/engine/engine_support_test.cc
+++ b/test/engine/engine_support_test.cc
@@ -692,7 +692,7 @@ TEST_F(SupportTest, GetSetStateStepEqual) {
 using AddMTest = MujocoTest;
 
 TEST_F(AddMTest, DenseSameAsSparse) {
-  mjModel* m = LoadModelFromPath("humanoid100/humanoid100.xml");
+  mjModel* m = LoadModelFromPath("humanoid/humanoid100.xml");
   mjData* d = mj_makeData(m);
   int nv = m->nv;
 
diff --git a/test/sample/compile_test.sh b/test/sample/compile_test.sh
index b431ffce..d45151f1 100755
--- a/test/sample/compile_test.sh
+++ b/test/sample/compile_test.sh
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-MODEL="${CMAKE_SOURCE_DIR}/model/humanoid100/humanoid100.xml"
+MODEL="${CMAKE_SOURCE_DIR}/model/humanoid/humanoid100.xml"
 OUTPUT_FILE="${TEST_TMPDIR}/compiled.mjb"