diff --git a/tests/test_glm45_parser.py b/tests/test_glm45_parser.py
new file mode 100644
index 0000000..98e8315
--- /dev/null
+++ b/tests/test_glm45_parser.py
@@ -0,0 +1,131 @@
+"""Tests for the glm45 chat template (a plain GeneralParser).
+
+glm45 is registered as a GeneralParser template (``parser_type`` defaults to
+"general"), NOT a custom parser class. GLM's chat format is a flat
+``<|user|>``/``<|assistant|>`` header structure with ``<think>...</think>``
+reasoning merged inline into the assistant content, so
+``tokenizer.apply_chat_template`` + a single end-of-turn terminator produce the
+correct last-assistant-turn loss mask. These tests lock in that decision:
+
+  * glm45 dispatches to ``GeneralParser`` (and explicitly NOT ``ThinkingParser``,
+    whose last-turn reconstruction would double GLM's already-open ``<think>``).
+  * the rendered assistant turn keeps a single ``<think>`` block (no doubling).
+  * the last assistant turn — including its ``<think>`` reasoning — is fully
+    loss-masked, while earlier turns are excluded under ``last_turn_only``.
+
+Loss-mask agreement with the runtime numba mask is cross-validated generically in
+``test_loss_mask_cross_validation.py`` (glm45 is in ``REFERENCE_MODELS``).
+
+The render/mask tests need GLM's real chat template, so they load the GLM-4.5
+tokenizer (the glm45 grammar is shared 4.5 -> 5.2; 4.5 loads cleanly via
+``AutoTokenizer``) and skip when it is unavailable.
+"""
+
+import pytest
+
+from torchspec.data.parse import GeneralParser, ThinkingParser, create_parser
+from torchspec.data.template import TEMPLATE_REGISTRY
+
+GLM_MODEL = "zai-org/GLM-4.5"
+_tokenizer_cache: dict = {}
+
+
+def _glm_tokenizer():
+    if GLM_MODEL in _tokenizer_cache:
+        return _tokenizer_cache[GLM_MODEL]
+    from transformers import AutoTokenizer
+
+    try:
+        tokenizer = AutoTokenizer.from_pretrained(GLM_MODEL, trust_remote_code=True)
+    except Exception as e:  # noqa: BLE001 — any download/load failure -> skip
+        pytest.skip(f"GLM tokenizer unavailable for {GLM_MODEL}: {e}")
+    _tokenizer_cache[GLM_MODEL] = tokenizer
+    return tokenizer
+
+
+@pytest.fixture
+def glm45_template():
+    return TEMPLATE_REGISTRY.get("glm45")
+
+
+class TestGlm45TemplateRegistration:
+    def test_template_registered(self):
+        assert "glm45" in TEMPLATE_REGISTRY.get_all_template_names()
+
+    def test_template_attributes(self, glm45_template):
+        assert glm45_template.assistant_header == "<|assistant|>"
+        assert glm45_template.user_header == "<|user|>"
+        # GLM has no dedicated assistant end token; a turn ends at the next role
+        # header, so the terminator is the user header.
+        assert glm45_template.end_of_turn_token == "<|user|>"
+        assert glm45_template.system_prompt is None
+        # Default "general" -> GeneralParser. NOT "thinking": GLM's generation
+        # prompt already opens <think>, so ThinkingParser's reconstruction would
+        # double it (<think><think>).
+        assert glm45_template.parser_type == "general"
+
+
+class TestGlm45ParserDispatch:
+    def test_dispatches_to_general_parser(self, glm45_template):
+        # create_parser only reads the template in __init__ (no tokenizer method
+        # is called), so this assertion runs fully offline.
+        parser = create_parser(object(), glm45_template)
+        assert isinstance(parser, GeneralParser)
+        assert not isinstance(parser, ThinkingParser)
+
+
+class TestGlm45RenderAndMask:
+    """Exercises GLM's real chat template; skips if the tokenizer is unavailable."""
+
+    SINGLE_TURN = [
+        {"role": "user", "content": "What is 2+2?"},
+        {"role": "assistant", "content": "<think>add two and two</think>The answer is 4."},
+    ]
+
+    MULTI_TURN = [
+        {"role": "user", "content": "First question"},
+        {"role": "assistant", "content": "<think>first reasoning</think>First answer here."},
+        {"role": "user", "content": "Second question"},
+        {"role": "assistant", "content": "<think>second reasoning</think>Second answer here."},
+    ]
+
+    def test_single_think_no_doubling(self, glm45_template):
+        tokenizer = _glm_tokenizer()
+        parser = create_parser(tokenizer, glm45_template)
+        rendered = parser.format(self.SINGLE_TURN, add_generation_prompt=False)
+        assistant = rendered.split("<|assistant|>", 1)[1]
+        assert assistant.count("<think>") == 1
+        assert assistant.count("</think>") == 1
+        assert "add two and two" in assistant
+
+    def test_last_turn_reasoning_is_supervised(self, glm45_template):
+        tokenizer = _glm_tokenizer()
+        parser = create_parser(tokenizer, glm45_template)
+        rendered = parser.format(self.SINGLE_TURN, add_generation_prompt=False)
+        ids, mask = parser.parse(
+            rendered, max_length=200000, preformatted=True, last_turn_only=True
+        )
+        ids_list = ids.squeeze().tolist()
+        mask_list = mask.squeeze().tolist()
+        assert sum(mask_list) > 0
+        masked = tokenizer.decode([i for i, m in zip(ids_list, mask_list) if m == 1])
+        # Both the inline reasoning AND the answer are training targets for the draft.
+        assert "add two and two" in masked
+        assert "The answer is 4" in masked
+
+    def test_only_last_turn_masked(self, glm45_template):
+        tokenizer = _glm_tokenizer()
+        parser = create_parser(tokenizer, glm45_template)
+        rendered = parser.format(self.MULTI_TURN, add_generation_prompt=False)
+        ids, mask = parser.parse(
+            rendered, max_length=200000, preformatted=True, last_turn_only=True
+        )
+        ids_list = ids.squeeze().tolist()
+        mask_list = mask.squeeze().tolist()
+        masked = tokenizer.decode([i for i, m in zip(ids_list, mask_list) if m == 1])
+        # Last turn (reasoning + answer) is supervised...
+        assert "second reasoning" in masked
+        assert "Second answer here." in masked
+        # ...and the earlier assistant turn is excluded under last_turn_only.
+        assert "first reasoning" not in masked
+        assert "First answer here." not in masked
diff --git a/tests/test_loss_mask_cross_validation.py b/tests/test_loss_mask_cross_validation.py
index 411b532..92f0166 100644
--- a/tests/test_loss_mask_cross_validation.py
+++ b/tests/test_loss_mask_cross_validation.py
@@ -46,6 +46,11 @@
     "ling-flash-2.0": "inclusionAI/Ling-lite",
     "deepseek-v32": "deepseek-ai/DeepSeek-V3",
     "minimax-m2": "MiniMaxAI/MiniMax-M2.5",
+    # GLM grammar is a continuous family (4.5 -> 5.2); GLM-4.5 loads cleanly via
+    # AutoTokenizer, while GLM-5.2's tokenizer_config declares the transformers-v5
+    # TokenizersBackend class and would skip here. 4.5 is representative for the
+    # shared glm45 template.
+    "glm45": "zai-org/GLM-4.5",
 }
 
 _tokenizer_cache: dict = {}
diff --git a/torchspec/data/template.py b/torchspec/data/template.py
index bb788d4..3bc292a 100644
--- a/torchspec/data/template.py
+++ b/torchspec/data/template.py
@@ -266,3 +266,13 @@ def get_all_template_names(self) -> List[str]:
         image_placeholder="<image>",
     ),
 )
+
+TEMPLATE_REGISTRY.register(
+    name="glm45",
+    template=ChatTemplate(
+        assistant_header="<|assistant|>",
+        user_header="<|user|>",
+        system_prompt=None,
+        end_of_turn_token="<|user|>",
+    ),
+)