diff --git a/readthedocs/config/config.py b/readthedocs/config/config.py
index b5e56c98d48..3373c89bc7f 100644
--- a/readthedocs/config/config.py
+++ b/readthedocs/config/config.py
@@ -167,6 +167,10 @@ def validate(self):
     def is_using_conda(self):
         return self.python_interpreter in ("conda", "mamba")
 
+    @property
+    def is_using_build_commands(self):
+        return self.build.commands != []
+
     @property
     def is_using_setup_py_install(self):
         """Check if this project is using `setup.py install` as installation method."""
@@ -260,7 +264,7 @@ def validate_conda(self):
         """Validates the conda key."""
         raw_conda = self._raw_config.get('conda')
         if raw_conda is None:
-            if self.is_using_conda:
+            if self.is_using_conda and not self.is_using_build_commands:
                 raise ConfigError(
                     message_id=ConfigError.CONDA_KEY_REQUIRED,
                     format_values={"key": "conda"},
diff --git a/readthedocs/config/tests/test_config.py b/readthedocs/config/tests/test_config.py
index 64e9ccf14ad..8acab42b064 100644
--- a/readthedocs/config/tests/test_config.py
+++ b/readthedocs/config/tests/test_config.py
@@ -2,6 +2,7 @@
 import re
 import textwrap
 from collections import OrderedDict
+from contextlib import nullcontext as does_not_raise
 
 import pytest
 from django.conf import settings
@@ -293,12 +294,28 @@ def test_conda_key_required_for_conda_mamba(self):
                 },
             }
         )
-        print(build)
         with raises(ConfigError) as excinfo:
             build.validate()
         assert excinfo.value.message_id == ConfigError.CONDA_KEY_REQUIRED
         assert excinfo.value.format_values.get("key") == "conda"
 
+    def test_conda_key_not_required_for_conda_mamba_when_build_commands(self):
+        build = get_build_config(
+            {
+                "build": {
+                    "os": "ubuntu-22.04",
+                    "tools": {
+                        "python": "mambaforge-22.9",
+                    },
+                    "commands": [
+                        "mamba env create --file environment.yml",
+                    ],
+                },
+            }
+        )
+        with does_not_raise(ConfigError):
+            build.validate()
+
     @pytest.mark.parametrize("value", [3, [], "invalid"])
     def test_conda_check_invalid_value(self, value):
         build = get_build_config({"conda": value})