diff --git a/src/Microsoft.FeatureManagement/ConfigurationFeatureDefinitionProvider.cs b/src/Microsoft.FeatureManagement/ConfigurationFeatureDefinitionProvider.cs
index 276f4822..5b30f56e 100644
--- a/src/Microsoft.FeatureManagement/ConfigurationFeatureDefinitionProvider.cs
+++ b/src/Microsoft.FeatureManagement/ConfigurationFeatureDefinitionProvider.cs
@@ -56,6 +56,11 @@ public Task<FeatureDefinition> GetFeatureDefinitionAsync(string featureName)
                 throw new ArgumentNullException(nameof(featureName));
             }
 
+            if (featureName.Contains(ConfigurationPath.KeyDelimiter))
+            {
+                throw new ArgumentException($"The value '{ConfigurationPath.KeyDelimiter}' is not allowed in the feature name.", nameof(featureName));
+            }
+
             if (Interlocked.Exchange(ref _stale, 0) != 0)
             {
                 _definitions.Clear();