diff --git a/blueprintcompiler/errors.py b/blueprintcompiler/errors.py
index 2a14040..e89ec31 100644
--- a/blueprintcompiler/errors.py
+++ b/blueprintcompiler/errors.py
@@ -128,6 +128,10 @@ class CompileWarning(CompileError):
     color = Colors.YELLOW
 
 
+class DeprecatedWarning(CompileWarning):
+    pass
+
+
 class UpgradeWarning(CompileWarning):
     category = "upgrade"
     color = Colors.PURPLE
diff --git a/blueprintcompiler/language/common.py b/blueprintcompiler/language/common.py
index f1c6bb9..e45cddc 100644
--- a/blueprintcompiler/language/common.py
+++ b/blueprintcompiler/language/common.py
@@ -33,6 +33,7 @@ from ..errors import (
     CodeAction,
     CompileError,
     CompileWarning,
+    DeprecatedWarning,
     MultipleErrors,
     UpgradeWarning,
 )
diff --git a/blueprintcompiler/language/gobject_property.py b/blueprintcompiler/language/gobject_property.py
index 526b308..68f8c6d 100644
--- a/blueprintcompiler/language/gobject_property.py
+++ b/blueprintcompiler/language/gobject_property.py
@@ -99,7 +99,7 @@ class Property(AstNode):
             hints = []
             if self.gir_property.deprecated_doc:
                 hints.append(self.gir_property.deprecated_doc)
-            raise CompileWarning(
+            raise DeprecatedWarning(
                 f"{self.gir_property.signature} is deprecated",
                 hints=hints,
             )
diff --git a/blueprintcompiler/language/gobject_signal.py b/blueprintcompiler/language/gobject_signal.py
index 1c60bbf..721c443 100644
--- a/blueprintcompiler/language/gobject_signal.py
+++ b/blueprintcompiler/language/gobject_signal.py
@@ -142,7 +142,7 @@ class Signal(AstNode):
             hints = []
             if self.gir_signal.deprecated_doc:
                 hints.append(self.gir_signal.deprecated_doc)
-            raise CompileWarning(
+            raise DeprecatedWarning(
                 f"{self.gir_signal.signature} is deprecated",
                 hints=hints,
             )
diff --git a/blueprintcompiler/language/types.py b/blueprintcompiler/language/types.py
index 1d9911b..e7b1867 100644
--- a/blueprintcompiler/language/types.py
+++ b/blueprintcompiler/language/types.py
@@ -63,7 +63,7 @@ class TypeName(AstNode):
             hints = []
             if self.gir_type.deprecated_doc:
                 hints.append(self.gir_type.deprecated_doc)
-            raise CompileWarning(
+            raise DeprecatedWarning(
                 f"{self.gir_type.full_name} is deprecated",
                 hints=hints,
             )
diff --git a/blueprintcompiler/lsp.py b/blueprintcompiler/lsp.py
index e8c37f3..54a36c8 100644
--- a/blueprintcompiler/lsp.py
+++ b/blueprintcompiler/lsp.py
@@ -391,6 +391,9 @@ class LanguageServer:
             else DiagnosticSeverity.Error,
         }
 
+        if isinstance(err, DeprecationWarning):
+            result["tags"] = [DiagnosticTag.Deprecated]
+
         if len(err.references) > 0:
             result["relatedInformation"] = [
                 {
diff --git a/blueprintcompiler/lsp_utils.py b/blueprintcompiler/lsp_utils.py
index 7f46680..2d1072e 100644
--- a/blueprintcompiler/lsp_utils.py
+++ b/blueprintcompiler/lsp_utils.py
@@ -119,6 +119,11 @@ class DiagnosticSeverity(enum.IntEnum):
     Hint = 4
 
 
+class DiagnosticTag(enum.IntEnum):
+    Unnecessary = 1
+    Deprecated = 2
+
+
 @dataclass
 class SemanticToken:
     start: int
diff --git a/tests/test_samples.py b/tests/test_samples.py
index 1273805..bacca80 100644
--- a/tests/test_samples.py
+++ b/tests/test_samples.py
@@ -29,7 +29,12 @@ from gi.repository import Gtk
 
 from blueprintcompiler import decompiler, parser, tokenizer, utils
 from blueprintcompiler.completions import complete
-from blueprintcompiler.errors import CompileError, MultipleErrors, PrintableError
+from blueprintcompiler.errors import (
+    CompileError,
+    DeprecatedWarning,
+    MultipleErrors,
+    PrintableError,
+)
 from blueprintcompiler.outputs.xml import XmlOutput
 from blueprintcompiler.tokenizer import Token, TokenType, tokenize
 
@@ -59,7 +64,7 @@ class TestSamples(unittest.TestCase):
             warnings = [
                 warning
                 for warning in warnings
-                if "is deprecated" not in warning.message
+                if not isinstance(warning, DeprecatedWarning)
             ]
 
             if errors: