diff --git a/clang-tools-extra/clangd/ClangdLSPServer.cpp b/clang-tools-extra/clangd/ClangdLSPServer.cpp
--- a/clang-tools-extra/clangd/ClangdLSPServer.cpp
+++ b/clang-tools-extra/clangd/ClangdLSPServer.cpp
@@ -1397,14 +1397,15 @@
 
 void ClangdLSPServer::onSemanticTokens(const SemanticTokensParams &Params,
                                        Callback<SemanticTokens> CB) {
+  auto File = Params.textDocument.uri.file();
   Server->semanticHighlights(
       Params.textDocument.uri.file(),
-      [this, File(Params.textDocument.uri.file().str()), CB(std::move(CB))](
+      [this, File(File.str()), CB(std::move(CB)), Code(Server->getDraft(File))](
           llvm::Expected<std::vector<HighlightingToken>> HT) mutable {
         if (!HT)
           return CB(HT.takeError());
         SemanticTokens Result;
-        Result.tokens = toSemanticTokens(*HT);
+        Result.tokens = toSemanticTokens(*HT, *Code);
         {
           std::lock_guard<std::mutex> Lock(SemanticTokensMutex);
           auto &Last = LastSemanticTokens[File];
@@ -1420,14 +1421,15 @@
 void ClangdLSPServer::onSemanticTokensDelta(
     const SemanticTokensDeltaParams &Params,
     Callback<SemanticTokensOrDelta> CB) {
+  auto File = Params.textDocument.uri.file();
   Server->semanticHighlights(
       Params.textDocument.uri.file(),
-      [this, PrevResultID(Params.previousResultId),
-       File(Params.textDocument.uri.file().str()), CB(std::move(CB))](
+      [this, PrevResultID(Params.previousResultId), File(File.str()),
+       CB(std::move(CB)), Code(Server->getDraft(File))](
           llvm::Expected<std::vector<HighlightingToken>> HT) mutable {
         if (!HT)
           return CB(HT.takeError());
-        std::vector<SemanticToken> Toks = toSemanticTokens(*HT);
+        std::vector<SemanticToken> Toks = toSemanticTokens(*HT, *Code);
 
         SemanticTokensOrDelta Result;
         {
diff --git a/clang-tools-extra/clangd/SemanticHighlighting.h b/clang-tools-extra/clangd/SemanticHighlighting.h
--- a/clang-tools-extra/clangd/SemanticHighlighting.h
+++ b/clang-tools-extra/clangd/SemanticHighlighting.h
@@ -21,6 +21,7 @@
 #define LLVM_CLANG_TOOLS_EXTRA_CLANGD_SEMANTICHIGHLIGHTING_H
 
 #include "Protocol.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/raw_ostream.h"
 
 namespace clang {
@@ -101,7 +102,8 @@
 // main AST.
 std::vector<HighlightingToken> getSemanticHighlightings(ParsedAST &AST);
 
-std::vector<SemanticToken> toSemanticTokens(llvm::ArrayRef<HighlightingToken>);
+std::vector<SemanticToken> toSemanticTokens(llvm::ArrayRef<HighlightingToken>,
+                                            llvm::StringRef Code);
 llvm::StringRef toSemanticTokenType(HighlightingKind Kind);
 llvm::StringRef toSemanticTokenModifier(HighlightingModifier Modifier);
 std::vector<SemanticTokensEdit> diffTokens(llvm::ArrayRef<SemanticToken> Before,
diff --git a/clang-tools-extra/clangd/SemanticHighlighting.cpp b/clang-tools-extra/clangd/SemanticHighlighting.cpp
--- a/clang-tools-extra/clangd/SemanticHighlighting.cpp
+++ b/clang-tools-extra/clangd/SemanticHighlighting.cpp
@@ -30,7 +30,9 @@
 #include "llvm/ADT/None.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Casting.h"
+#include "llvm/Support/Error.h"
 #include <algorithm>
 
 namespace clang {
@@ -918,7 +920,8 @@
 }
 
 std::vector<SemanticToken>
-toSemanticTokens(llvm::ArrayRef<HighlightingToken> Tokens) {
+toSemanticTokens(llvm::ArrayRef<HighlightingToken> Tokens,
+                 llvm::StringRef Code) {
   assert(std::is_sorted(Tokens.begin(), Tokens.end()));
   std::vector<SemanticToken> Result;
   const HighlightingToken *Last = nullptr;
@@ -939,8 +942,22 @@
       Out.deltaLine = Tok.R.start.line;
       Out.deltaStart = Tok.R.start.character;
     }
-    assert(Tok.R.end.line == Tok.R.start.line);
-    Out.length = Tok.R.end.character - Tok.R.start.character;
+    if (Tok.R.end.line == Tok.R.start.line) {
+      Out.length = Tok.R.end.character - Tok.R.start.character;
+    } else {
+      // If a tokens length is past the end of the line, it should be treated as
+      // if the token ends at the end of the line and will not wrap onto the
+      // next line.
+      // This is slow, but code rarely has multiline tokens.
+      // FIXME: There's a client capability for supporting multiline tokens,
+      // respect that.
+      auto TokStartOffset = llvm::cantFail(positionToOffset(Code, Tok.R.start));
+      auto LineEnd = Code.find('\n', TokStartOffset);
+      if (LineEnd == Code.npos)
+        Out.length = Code.size() - TokStartOffset;
+      else
+        Out.length = LineEnd - TokStartOffset;
+    }
     Out.tokenType = static_cast<unsigned>(Tok.Kind);
     Out.tokenModifiers = Tok.Modifiers;
 
diff --git a/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp b/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
--- a/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
+++ b/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
@@ -944,7 +944,7 @@
   )");
   Tokens.front().Modifiers |= unsigned(HighlightingModifier::Declaration);
   Tokens.front().Modifiers |= unsigned(HighlightingModifier::Readonly);
-  auto Results = toSemanticTokens(Tokens);
+  auto Results = toSemanticTokens(Tokens, /*Code=*/"");
 
   ASSERT_THAT(Results, SizeIs(3));
   EXPECT_EQ(Results[0].tokenType, unsigned(HighlightingKind::Variable));
@@ -972,13 +972,15 @@
   auto Before = toSemanticTokens(tokens(R"(
     [[foo]] [[bar]] [[baz]]
     [[one]] [[two]] [[three]]
-  )"));
+  )"),
+                                 /*Code=*/"");
   EXPECT_THAT(diffTokens(Before, Before), IsEmpty());
 
   auto After = toSemanticTokens(tokens(R"(
     [[foo]] [[hello]] [[world]] [[baz]]
     [[one]] [[two]] [[three]]
-  )"));
+  )"),
+                                /*Code=*/"");
 
   // Replace [bar, baz] with [hello, world, baz]
   auto Diff = diffTokens(Before, After);
@@ -1000,6 +1002,23 @@
   EXPECT_EQ(3u, Diff.front().tokens[2].length);
 }
 
+TEST(SemanticHighlighting, MultilineTokens) {
+  llvm::StringRef AnnotatedCode = R"cpp(
+[[fo
+o]] [[bar]])cpp";
+  auto Toks = toSemanticTokens(tokens(AnnotatedCode),
+                               Annotations(AnnotatedCode).code());
+  ASSERT_THAT(Toks, SizeIs(2));
+  // foo
+  EXPECT_EQ(Toks[0].deltaLine, 1u);
+  EXPECT_EQ(Toks[0].deltaStart, 0u);
+  EXPECT_EQ(Toks[0].length, 2u);
+
+  // bar
+  EXPECT_EQ(Toks[1].deltaLine, 1u);
+  EXPECT_EQ(Toks[1].deltaStart, 2u);
+  EXPECT_EQ(Toks[1].length, 3u);
+}
 } // namespace
 } // namespace clangd
 } // namespace clang