diff --git a/json/json.go b/json/json.go
index 220057d..9bb7e95 100644
--- a/json/json.go
+++ b/json/json.go
@@ -368,8 +368,8 @@ func writeJSONScalar(ctx *jsonWriteContext, node *yaml.Node) error {
 		return nil
 
 	case "!!bool":
-		// Booleans
-		ctx.write(node.Value)
+		// Booleans true/True/TRUE to true compatible with JSON
+		ctx.write(strings.ToLower(node.Value))
 		return nil
 
 	case "!!null":
diff --git a/json/json_test.go b/json/json_test.go
index f189e1b..b6d1628 100644
--- a/json/json_test.go
+++ b/json/json_test.go
@@ -211,6 +211,20 @@ production:
     "host": "prod.example.com"
   }
 }
+`,
+			indentation: 2,
+		},
+		{
+			name: "booleans",
+			yamlInput: `lowerCaseBool: true
+mixedCaseBool: True
+upperCaseBool: FALSE
+`,
+			expectedJSON: `{
+  "lowerCaseBool": true,
+  "mixedCaseBool": true,
+  "upperCaseBool": false
+}
 `,
 			indentation: 2,
 		},