diff --git a/src/built_in_type_definitions.rs b/src/built_in_type_definitions.rs
index 8d97630..7a33962 100644
--- a/src/built_in_type_definitions.rs
+++ b/src/built_in_type_definitions.rs
@@ -5,6 +5,7 @@ use enum_iterator::{all, Sequence};
 use crate::{EnumDefinition, Identifier, Type, TypeDefinition, VariantContent};
 
 static OPTION: OnceLock<TypeDefinition> = OnceLock::new();
+static RESULT: OnceLock<TypeDefinition> = OnceLock::new();
 
 pub fn all_built_in_type_definitions() -> impl Iterator<Item = BuiltInTypeDefinition> {
     all()
@@ -13,12 +14,14 @@ pub fn all_built_in_type_definitions() -> impl Iterator<Item = BuiltInTypeDefini
 #[derive(Sequence)]
 pub enum BuiltInTypeDefinition {
     Option,
+    Result,
 }
 
 impl BuiltInTypeDefinition {
     pub fn name(&self) -> &'static str {
         match self {
             BuiltInTypeDefinition::Option => "Option",
+            BuiltInTypeDefinition::Result => "Result",
         }
     }
 
@@ -26,13 +29,22 @@ impl BuiltInTypeDefinition {
         match self {
             BuiltInTypeDefinition::Option => OPTION.get_or_init(|| {
                 TypeDefinition::Enum(EnumDefinition::new(
-                    Identifier::new("Option"),
+                    Identifier::new(self.name()),
                     vec![
                         (Identifier::new("Some"), VariantContent::Type(Type::Any)),
                         (Identifier::new("None"), VariantContent::None),
                     ],
                 ))
             }),
+            BuiltInTypeDefinition::Result => RESULT.get_or_init(|| {
+                TypeDefinition::Enum(EnumDefinition::new(
+                    Identifier::new(self.name()),
+                    vec![
+                        (Identifier::new("Ok"), VariantContent::Type(Type::Any)),
+                        (Identifier::new("Err"), VariantContent::Type(Type::Any)),
+                    ],
+                ))
+            }),
         }
     }
 }
diff --git a/tests/built_in_type_definitions.rs b/tests/built_in_type_definitions.rs
index 39fedf5..0ff3051 100644
--- a/tests/built_in_type_definitions.rs
+++ b/tests/built_in_type_definitions.rs
@@ -36,4 +36,17 @@ fn result() {
             Value::Integer(1)
         )))
     );
+    assert_eq!(
+        interpret(
+            "
+            result = new Result:Error('uh-oh!')
+            result
+            "
+        ),
+        Ok(Value::Enum(EnumInstance::new(
+            "Result".to_string(),
+            "Error".to_string(),
+            Value::String("uh-oh!".to_string())
+        )))
+    );
 }