diff --git a/helix-core/src/diagnostic.rs b/helix-core/src/diagnostic.rs
index db1f2da9..6b5da17e 100644
--- a/helix-core/src/diagnostic.rs
+++ b/helix-core/src/diagnostic.rs
@@ -45,4 +45,5 @@ pub struct Diagnostic {
     pub code: Option<NumberOrString>,
     pub tags: Vec<DiagnosticTag>,
     pub source: Option<String>,
+    pub data: Option<serde_json::Value>,
 }
diff --git a/helix-lsp/src/lib.rs b/helix-lsp/src/lib.rs
index 5de76c6c..abc930f8 100644
--- a/helix-lsp/src/lib.rs
+++ b/helix-lsp/src/lib.rs
@@ -102,16 +102,17 @@ pub mod util {
             None
         };
 
-        // TODO: add support for Diagnostic.data
-        lsp::Diagnostic::new(
-            range_to_lsp_range(doc, range, offset_encoding),
+        lsp::Diagnostic {
+            range: range_to_lsp_range(doc, range, offset_encoding),
             severity,
             code,
-            diag.source.clone(),
-            diag.message.to_owned(),
-            None,
+            source: diag.source.clone(),
+            message: diag.message.to_owned(),
+            related_information: None,
             tags,
-        )
+            data: diag.data.to_owned(),
+            ..Default::default()
+        }
     }
 
     /// Converts [`lsp::Position`] to a position in the document.
diff --git a/helix-term/src/application.rs b/helix-term/src/application.rs
index dc12ba3c..7a50e007 100644
--- a/helix-term/src/application.rs
+++ b/helix-term/src/application.rs
@@ -772,7 +772,8 @@ impl Application {
                                         severity,
                                         code,
                                         tags,
-                                        source: diagnostic.source.clone()
+                                        source: diagnostic.source.clone(),
+                                        data: diagnostic.data.clone(),
                                     })
                                 })
                                 .collect();