diff --git a/litellm/proxy/auth/auth_checks.py b/litellm/proxy/auth/auth_checks.py
index 19e4f158144..f6345eae06d 100644
--- a/litellm/proxy/auth/auth_checks.py
+++ b/litellm/proxy/auth/auth_checks.py
@@ -5620,6 +5620,11 @@ async def _model_access_group_max_budget_check(
     overshoot the ceiling slightly. The reservation counters are the precise path; this one covers
     the ``disable_budget_reservation`` case.
 
+    The ceiling is exclusive, unlike the tag check it otherwise mirrors: a pool whose recorded
+    spend has reached ``max_budget`` has nothing left to give, so the next request is refused.
+    Keys and organizations already draw the line there. A non-positive budget means no budget,
+    matching what the reservation path treats as unbudgeted.
+
     Raises:
         BudgetExceededError if a matched group is over its max budget.
     """
@@ -5636,7 +5641,7 @@ async def _model_access_group_max_budget_check(
 
     for group in matched_model_access_groups:
         budget = budgets.get(group)
-        if budget is None or budget.max_budget is None:
+        if budget is None or budget.max_budget is None or budget.max_budget <= 0:
             continue
 
         group_spend = await get_current_spend(
@@ -5645,7 +5650,7 @@ async def _model_access_group_max_budget_check(
             max_budget=budget.max_budget,
             fallback_authoritative=True,
         )
-        if group_spend <= budget.max_budget:
+        if group_spend < budget.max_budget:
             continue
         raise litellm.BudgetExceededError(
             current_cost=group_spend,
diff --git a/tests/test_litellm/proxy/auth/test_model_access_group_budgets.py b/tests/test_litellm/proxy/auth/test_model_access_group_budgets.py
index 4396dae202b..fb82d8708fd 100644
--- a/tests/test_litellm/proxy/auth/test_model_access_group_budgets.py
+++ b/tests/test_litellm/proxy/auth/test_model_access_group_budgets.py
@@ -364,19 +364,51 @@ async def test_group_under_its_max_budget_passes():
 
 
 @pytest.mark.asyncio
-async def test_group_exactly_at_its_max_budget_passes():
-    """The ceiling is inclusive, matching the tag check it mirrors; only spend strictly above it blocks.
+async def test_group_exactly_at_its_max_budget_blocks_the_request():
+    """A pool whose spend has reached the ceiling has nothing left, so the next request is refused.
 
-    Asserting the counter was read is what keeps this honest: a group that got skipped entirely,
-    because its row never arrived or carried no budget, would also not raise.
+    This is where the check departs from the tag one it otherwise mirrors, and it matches where
+    keys and organizations already draw the line.
     """
+    with pytest.raises(litellm.BudgetExceededError) as exc_info:
+        await _enforce(
+            ("tier-a",),
+            _MagBudgetRow("tier-a", max_budget=10.0),
+            spend_by_counter_key={MODEL_ACCESS_GROUP_COUNTER_KEY: 10.0},
+        )
+
+    assert exc_info.value.entity_id == "tier-a"
+    assert exc_info.value.current_cost == 10.0
+
+
+@pytest.mark.asyncio
+async def test_group_just_under_its_max_budget_passes():
+    """Asserting the counter was read is what keeps this honest: a group that got skipped entirely,
+    because its row never arrived or carried no budget, would also not raise."""
     assert await _enforce(
         ("tier-a",),
         _MagBudgetRow("tier-a", max_budget=10.0),
-        spend_by_counter_key={MODEL_ACCESS_GROUP_COUNTER_KEY: 10.0},
+        spend_by_counter_key={MODEL_ACCESS_GROUP_COUNTER_KEY: 9.99},
     ) == [MODEL_ACCESS_GROUP_COUNTER_KEY]
 
 
+@pytest.mark.asyncio
+async def test_a_non_positive_budget_means_no_budget():
+    """The reservation path treats max_budget <= 0 as unbudgeted, so the read-time check must agree.
+
+    Without this the exclusive ceiling would turn a zero into a total freeze on one path and a
+    no-op on the other.
+    """
+    assert (
+        await _enforce(
+            ("tier-a",),
+            _MagBudgetRow("tier-a", max_budget=0.0),
+            spend_by_counter_key={MODEL_ACCESS_GROUP_COUNTER_KEY: 5.0},
+        )
+        == []
+    )
+
+
 @pytest.mark.asyncio
 async def test_group_over_its_max_budget_blocks_the_request_and_names_the_group():
     with pytest.raises(litellm.BudgetExceededError) as exc_info: