diff --git a/src/post_training/slurm/job_trl_container.sh.jinja b/src/post_training/slurm/job_trl_container.sh.jinja
index 86699b0..989a947 100644
--- a/src/post_training/slurm/job_trl_container.sh.jinja
+++ b/src/post_training/slurm/job_trl_container.sh.jinja
@@ -30,6 +30,16 @@
 
 set -euo pipefail
 
+{% if modules %}
+# ── Environment modules ────────────────────────────────────────────────────
+{% if module_purge %}
+module purge
+{% endif %}
+{% for mod in modules %}
+module load {{ mod }}
+{% endfor %}
+{% endif %}
+
 # ── Source cluster environment ────────────────────────────────────────────
 {% if env_file %}source "{{ env_file }}"{% endif %}
 
diff --git a/src/post_training/slurm/launcher.py b/src/post_training/slurm/launcher.py
index 000bce4..fd8338f 100644
--- a/src/post_training/slurm/launcher.py
+++ b/src/post_training/slurm/launcher.py
@@ -128,6 +128,8 @@ def render_trl_container_slurm_script(
         wall_time=config.slurm.wall_time,
         signal_time_seconds=config.slurm.signal_time_seconds,
         max_failures=config.slurm.max_failures,
+        modules=config.slurm.modules,
+        module_purge=config.slurm.module_purge,
         run_dir=str(run_dir.resolve()),
         config_path=config_path,
         tokenize_only=tokenize_only,
diff --git a/tests/test_slurm_render.py b/tests/test_slurm_render.py
index 6b2adba..a0da377 100644
--- a/tests/test_slurm_render.py
+++ b/tests/test_slurm_render.py
@@ -139,6 +139,56 @@ def test_trl_container_qos_mem_absent_when_none(tmp_path, config):
     assert "--mem" not in content
 
 
+# ---------------------------------------------------------------------------
+# environment modules — TRL container template
+# ---------------------------------------------------------------------------
+
+
+def test_trl_container_modules_rendered(tmp_path, config):
+    """Configured host modules are loaded before the cluster environment file."""
+    config.slurm.modules = ["singularity/4.1.0", "cuda/12.4"]
+    config.slurm.module_purge = True
+    run_dir = tmp_path / "outputs" / "my-run"
+    run_dir.mkdir(parents=True)
+
+    content = render_trl_container_slurm_script(config, run_dir, "configs/trl/sft.yaml").read_text()
+
+    commands = [
+        "module purge",
+        "module load singularity/4.1.0",
+        "module load cuda/12.4",
+        'source "/shared/env/cluster.env"',
+    ]
+    assert all(command in content for command in commands)
+    assert [content.index(command) for command in commands] == sorted(
+        content.index(command) for command in commands
+    )
+
+
+def test_trl_container_module_purge_omitted_when_disabled(tmp_path, config):
+    """Modules can be loaded without first purging the inherited module set."""
+    config.slurm.modules = ["singularity/4.1.0"]
+    config.slurm.module_purge = False
+    run_dir = tmp_path / "outputs" / "my-run"
+    run_dir.mkdir(parents=True)
+
+    content = render_trl_container_slurm_script(config, run_dir, "configs/trl/sft.yaml").read_text()
+
+    assert "module load singularity/4.1.0" in content
+    assert "module purge" not in content
+
+
+def test_trl_container_host_setup_absent_when_unspecified(tmp_path, config):
+    """No module setup is rendered when the module list is empty."""
+    run_dir = tmp_path / "outputs" / "my-run"
+    run_dir.mkdir(parents=True)
+
+    content = render_trl_container_slurm_script(config, run_dir, "configs/trl/sft.yaml").read_text()
+
+    assert "module purge" not in content
+    assert "module load" not in content
+
+
 # ---------------------------------------------------------------------------
 # --tokenize-only forwarding — TRL templates and backend dispatch
 # ---------------------------------------------------------------------------