diff --git a/schemars/src/flatten.rs b/schemars/src/flatten.rs
index 930f8de..3a22888 100644
--- a/schemars/src/flatten.rs
+++ b/schemars/src/flatten.rs
@@ -32,7 +32,7 @@ macro_rules! impl_merge {
 impl_merge!(SchemaObject {
     merge: definitions extensions instance_type enum_values
         number string array object,
-    or: schema id title description format all_of any_of one_of not
+    or: schema id title description format const_value all_of any_of one_of not
         if_schema then_schema else_schema,
 });
 
diff --git a/schemars/src/schema.rs b/schemars/src/schema.rs
index b0bb506..3074c51 100644
--- a/schemars/src/schema.rs
+++ b/schemars/src/schema.rs
@@ -47,13 +47,13 @@ pub struct SchemaObject {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub description: Option<String>,
     #[serde(rename = "type", skip_serializing_if = "Option::is_none")]
-    // TODO Set instead of Vec
     pub instance_type: Option<SingleOrVec<InstanceType>>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub format: Option<String>,
     #[serde(rename = "enum", skip_serializing_if = "Option::is_none")]
-    // TODO Set instead of Vec
     pub enum_values: Option<Vec<Value>>,
+    #[serde(rename = "const", skip_serializing_if = "Option::is_none")]
+    pub const_value: Option<Value>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub all_of: Option<Vec<Schema>>,
     #[serde(skip_serializing_if = "Option::is_none")]
diff --git a/schemars/tests/expected/schema-openapi3.json b/schemars/tests/expected/schema-openapi3.json
index 82f5f04..9ad9317 100644
--- a/schemars/tests/expected/schema-openapi3.json
+++ b/schemars/tests/expected/schema-openapi3.json
@@ -101,6 +101,9 @@
           },
           "nullable": true
         },
+        "const": {
+          "nullable": true
+        },
         "contains": {
           "anyOf": [
             {
diff --git a/schemars/tests/expected/schema.json b/schemars/tests/expected/schema.json
index 10eaf9f..4c84b1d 100644
--- a/schemars/tests/expected/schema.json
+++ b/schemars/tests/expected/schema.json
@@ -117,6 +117,7 @@
             }
           ]
         },
+        "const": true,
         "contains": {
           "anyOf": [
             {