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
@@ -839,7 +839,17 @@
 void ClangdLSPServer::onHover(const TextDocumentPositionParams &Params,
                               Callback<llvm::Optional<Hover>> Reply) {
   Server->findHover(Params.textDocument.uri.file(), Params.position,
-                    std::move(Reply));
+                    Bind(
+                        [](decltype(Reply) Reply,
+                           llvm::Expected<llvm::Optional<HoverInfo>> HIorErr) {
+                          if (!HIorErr)
+                            return Reply(HIorErr.takeError());
+                          const auto &HI = HIorErr.get();
+                          if (!HI)
+                            return Reply(llvm::None);
+                          return Reply(HI->render());
+                        },
+                        std::move(Reply)));
 }
 
 void ClangdLSPServer::onTypeHierarchy(
diff --git a/clang-tools-extra/clangd/ClangdServer.h b/clang-tools-extra/clangd/ClangdServer.h
--- a/clang-tools-extra/clangd/ClangdServer.h
+++ b/clang-tools-extra/clangd/ClangdServer.h
@@ -180,7 +180,7 @@
 
   /// Get code hover for a given position.
   void findHover(PathRef File, Position Pos,
-                 Callback<llvm::Optional<Hover>> CB);
+                 Callback<llvm::Optional<HoverInfo>> CB);
 
   /// Get information about type hierarchy for a given position.
   void typeHierarchy(PathRef File, Position Pos, int Resolve,
diff --git a/clang-tools-extra/clangd/ClangdServer.cpp b/clang-tools-extra/clangd/ClangdServer.cpp
--- a/clang-tools-extra/clangd/ClangdServer.cpp
+++ b/clang-tools-extra/clangd/ClangdServer.cpp
@@ -523,8 +523,8 @@
 }
 
 void ClangdServer::findHover(PathRef File, Position Pos,
-                             Callback<llvm::Optional<Hover>> CB) {
-  auto Action = [Pos](Callback<llvm::Optional<Hover>> CB,
+                             Callback<llvm::Optional<HoverInfo>> CB) {
+  auto Action = [Pos](Callback<llvm::Optional<HoverInfo>> CB,
                       llvm::Expected<InputsAndAST> InpAST) {
     if (!InpAST)
       return CB(InpAST.takeError());
diff --git a/clang-tools-extra/clangd/XRefs.h b/clang-tools-extra/clangd/XRefs.h
--- a/clang-tools-extra/clangd/XRefs.h
+++ b/clang-tools-extra/clangd/XRefs.h
@@ -16,7 +16,10 @@
 #include "ClangdUnit.h"
 #include "Protocol.h"
 #include "index/Index.h"
+#include "index/SymbolLocation.h"
+#include "clang/Index/IndexSymbol.h"
 #include "llvm/ADT/Optional.h"
+#include "llvm/Support/raw_ostream.h"
 #include <vector>
 
 namespace clang {
@@ -46,8 +49,37 @@
 std::vector<DocumentHighlight> findDocumentHighlights(ParsedAST &AST,
                                                       Position Pos);
 
+struct HoverInfo {
+  using Type = std::string;
+  struct Param {
+    Type T;
+    std::string Name;
+    std::string Default;
+  };
+
+  LocatedSymbol Sym;
+  /// Fully qualiffied name for the scope containing the Sym.
+  std::string Scope;
+  std::string ParentScope;
+  SymbolKind Kind;
+  std::string Documentation;
+  /// Line containing the definition of the symbol.
+  std::string Definition;
+
+  /// T and ReturnType are mutually exclusive.
+  llvm::Optional<Type> T;
+  llvm::Optional<Type> ReturnType;
+  llvm::Optional<std::vector<Param>> Parameters;
+  llvm::Optional<std::vector<Param>> TemplateParameters;
+
+  /// Lower to LSP struct.
+  Hover render() const;
+};
+llvm::raw_ostream &operator<<(llvm::raw_ostream &, const HoverInfo::Param &);
+llvm::raw_ostream &operator<<(llvm::raw_ostream &, const HoverInfo &);
+
 /// Get the hover information when hovering at \p Pos.
-llvm::Optional<Hover> getHover(ParsedAST &AST, Position Pos);
+llvm::Optional<HoverInfo> getHover(ParsedAST &AST, Position Pos);
 
 /// Returns reference locations of the symbol at a specified \p Pos.
 /// \p Limit limits the number of results returned (0 means no limit).
diff --git a/clang-tools-extra/clangd/XRefs.cpp b/clang-tools-extra/clangd/XRefs.cpp
--- a/clang-tools-extra/clangd/XRefs.cpp
+++ b/clang-tools-extra/clangd/XRefs.cpp
@@ -7,21 +7,32 @@
 //===----------------------------------------------------------------------===//
 #include "XRefs.h"
 #include "AST.h"
+#include "CodeCompletionStrings.h"
 #include "FindSymbols.h"
 #include "Logger.h"
+#include "Protocol.h"
 #include "SourceCode.h"
 #include "URI.h"
 #include "index/Merge.h"
 #include "index/SymbolCollector.h"
 #include "index/SymbolLocation.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Decl.h"
 #include "clang/AST/DeclTemplate.h"
+#include "clang/AST/PrettyPrinter.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/Type.h"
+#include "clang/Basic/SourceLocation.h"
 #include "clang/Index/IndexDataConsumer.h"
 #include "clang/Index/IndexSymbol.h"
 #include "clang/Index/IndexingAction.h"
 #include "clang/Index/USRGeneration.h"
+#include "llvm/ADT/None.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/raw_ostream.h"
 
 namespace clang {
 namespace clangd {
@@ -241,17 +252,17 @@
   return {DeclMacrosFinder.getFoundDecls(), DeclMacrosFinder.takeMacroInfos()};
 }
 
-Range getTokenRange(ParsedAST &AST, SourceLocation TokLoc) {
-  const SourceManager &SourceMgr = AST.getASTContext().getSourceManager();
-  SourceLocation LocEnd = Lexer::getLocForEndOfToken(
-      TokLoc, 0, SourceMgr, AST.getASTContext().getLangOpts());
+Range getTokenRange(ASTContext &AST, SourceLocation TokLoc) {
+  const SourceManager &SourceMgr = AST.getSourceManager();
+  SourceLocation LocEnd =
+      Lexer::getLocForEndOfToken(TokLoc, 0, SourceMgr, AST.getLangOpts());
   return {sourceLocToPosition(SourceMgr, TokLoc),
           sourceLocToPosition(SourceMgr, LocEnd)};
 }
 
-llvm::Optional<Location> makeLocation(ParsedAST &AST, SourceLocation TokLoc,
+llvm::Optional<Location> makeLocation(ASTContext &AST, SourceLocation TokLoc,
                                       llvm::StringRef TUPath) {
-  const SourceManager &SourceMgr = AST.getASTContext().getSourceManager();
+  const SourceManager &SourceMgr = AST.getSourceManager();
   const FileEntry *F = SourceMgr.getFileEntryForID(SourceMgr.getFileID(TokLoc));
   if (!F)
     return None;
@@ -299,8 +310,8 @@
   // As a consequence, there's no need to look them up in the index either.
   std::vector<LocatedSymbol> Result;
   for (auto M : Symbols.Macros) {
-    if (auto Loc =
-            makeLocation(AST, M.Info->getDefinitionLoc(), *MainFilePath)) {
+    if (auto Loc = makeLocation(AST.getASTContext(), M.Info->getDefinitionLoc(),
+                                *MainFilePath)) {
       LocatedSymbol Macro;
       Macro.Name = M.Name;
       Macro.PreferredDeclaration = *Loc;
@@ -320,7 +331,7 @@
 
   // Emit all symbol locations (declaration or definition) from AST.
   for (const Decl *D : Symbols.Decls) {
-    auto Loc = makeLocation(AST, findNameLoc(D), *MainFilePath);
+    auto Loc = makeLocation(AST.getASTContext(), findNameLoc(D), *MainFilePath);
     if (!Loc)
       continue;
 
@@ -453,7 +464,7 @@
   std::vector<DocumentHighlight> Result;
   for (const auto &Ref : References) {
     DocumentHighlight DH;
-    DH.range = getTokenRange(AST, Ref.Loc);
+    DH.range = getTokenRange(AST.getASTContext(), Ref.Loc);
     if (Ref.Role & index::SymbolRoleSet(index::SymbolRole::Write))
       DH.kind = DocumentHighlightKind::Write;
     else if (Ref.Role & index::SymbolRoleSet(index::SymbolRole::Read))
@@ -525,54 +536,206 @@
   return None;
 }
 
-/// Generate a \p Hover object given the declaration \p D.
-static Hover getHoverContents(const Decl *D) {
-  Hover H;
-  llvm::Optional<std::string> NamedScope = getScopeName(D);
+static QualType getDeclType(const Decl *D) {
+  if (const TypedefNameDecl *TDD = dyn_cast<TypedefNameDecl>(D))
+    return TDD->getUnderlyingType();
+  if (const ValueDecl *VD = dyn_cast<ValueDecl>(D))
+    return VD->getType();
+  if (const TagDecl *TD = dyn_cast<TagDecl>(D))
+    return TD->getTypeForDecl()->getCanonicalTypeInternal();
+  return QualType();
+}
 
-  // Generate the "Declared in" section.
-  if (NamedScope) {
-    assert(!NamedScope->empty());
+static llvm::Optional<Location> getDeclLoc(const SourceLocation &SL,
+                                           ASTContext &AST) {
+  if (SL.isInvalid())
+    return llvm::None;
+  const auto &SM = AST.getSourceManager();
+  auto MainFilePath =
+      getCanonicalPath(SM.getFileEntryForID(SM.getMainFileID()), SM);
+  if (!MainFilePath) {
+    elog("Couldn't get main file path for: {0}", SL.printToString(SM));
+    return llvm::None;
+  }
+  return makeLocation(AST, SL, *MainFilePath);
+}
 
-    H.contents.value += "Declared in ";
-    H.contents.value += *NamedScope;
-    H.contents.value += "\n\n";
+static std::string getDefinitionLine(const Decl *D) {
+  std::string Definition;
+  {
+    llvm::raw_string_ostream OS(Definition);
+    PrintingPolicy Policy =
+        printingPolicyForDecls(D->getASTContext().getPrintingPolicy());
+    D->print(OS, Policy);
   }
+  return Definition;
+}
 
-  // We want to include the template in the Hover.
-  if (TemplateDecl *TD = D->getDescribedTemplate())
-    D = TD;
+llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
+                              const std::vector<HoverInfo::Param> &Params) {
+  for (size_t I = 0, E = Params.size(); I != E; ++I) {
+    if (I)
+      OS << ", ";
+    OS << Params.at(I);
+  }
+  return OS;
+}
 
-  std::string DeclText;
-  llvm::raw_string_ostream OS(DeclText);
+static std::vector<HoverInfo::Param>
+fetchTemplateParameters(const TemplateParameterList *Params,
+                        const PrintingPolicy &PP) {
+  assert(Params);
+  std::vector<HoverInfo::Param> TempParameters;
+
+  for (const Decl *Param : *Params) {
+    HoverInfo::Param P;
+    if (const auto TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
+      P.T = TTP->wasDeclaredWithTypename() ? "typename" : "class";
+      if (TTP->isParameterPack())
+        P.T += "...";
+
+      llvm::raw_string_ostream Out(P.Name);
+      Out << *TTP;
+      if (TTP->hasDefaultArgument())
+        P.Default = TTP->getDefaultArgument().getAsString(PP);
+    } else if (const auto NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
+      if (IdentifierInfo *II = NTTP->getIdentifier())
+        P.Name = II->getName().str();
+
+      llvm::raw_string_ostream Out(P.T);
+      NTTP->getType().print(Out, PP);
+      if (NTTP->isParameterPack())
+        Out << "...";
+
+      if (NTTP->hasDefaultArgument()) {
+        llvm::raw_string_ostream Out(P.Default);
+        NTTP->getDefaultArgument()->printPretty(Out, nullptr, PP);
+      }
+    } else if (const auto TTPD = dyn_cast<TemplateTemplateParmDecl>(Param)) {
+      llvm::raw_string_ostream OS(P.T);
+      OS << "template <"
+         << fetchTemplateParameters(
+                TTPD->getDescribedTemplate()->getTemplateParameters(), PP)
+         << '>';
+      if (TTPD->hasDefaultArgument()) {
+        llvm::raw_string_ostream Out(P.Default);
+        TTPD->getDefaultArgument().getArgument().print(PP, Out);
+      }
+    } else {
+      std::string ParamSerial;
+      llvm::raw_string_ostream Out(ParamSerial);
+      Param->print(Out, PP);
+      Out.flush();
+      vlog("Unhandled template param: {0}", ParamSerial);
+      continue;
+    }
+    TempParameters.push_back(std::move(P));
+  }
+
+  return TempParameters;
+}
+
+/// Generate a \p Hover object given the declaration \p D.
+static HoverInfo getHoverContents(const Decl *D) {
+  HoverInfo HI;
 
   PrintingPolicy Policy =
       printingPolicyForDecls(D->getASTContext().getPrintingPolicy());
+  if (const NamedDecl *ND = llvm::dyn_cast<NamedDecl>(D)) {
+    HI.Documentation = getDeclComment(ND->getASTContext(), *ND);
+    HI.Sym.Name = printName(D->getASTContext(), *ND);
+    HI.Scope = printQualifiedName(*ND);
+  }
 
-  D->print(OS, Policy);
+  if (llvm::Optional<std::string> NamedScope = getScopeName(D)) {
+    assert(!NamedScope->empty());
+    HI.ParentScope = std::move(*NamedScope);
+  }
+  HI.Kind = indexSymbolKindToSymbolKind(index::getSymbolInfo(D).Kind);
 
-  OS.flush();
+  if (const TemplateDecl *TD = D->getDescribedTemplate()) {
+    HI.TemplateParameters =
+        fetchTemplateParameters(TD->getTemplateParameters(), Policy);
+    D = TD;
+  } else if (const FunctionDecl *FD = D->getAsFunction()) {
+    if (const auto FTD = FD->getDescribedTemplate()) {
+      HI.TemplateParameters =
+          fetchTemplateParameters(FTD->getTemplateParameters(), Policy);
+      D = FTD;
+    }
+  }
 
-  H.contents.value += DeclText;
-  return H;
+  if (const FunctionDecl *FD = D->getAsFunction()) {
+    HI.ReturnType.emplace();
+    llvm::raw_string_ostream OS(*HI.ReturnType);
+    FD->getReturnType().print(OS, Policy);
+
+    HI.Parameters.emplace();
+    for (const ParmVarDecl *PVD : FD->parameters()) {
+      HI.Parameters->emplace_back();
+      auto &P = HI.Parameters->back();
+      P.T = PVD->getNameAsString();
+      if (PVD->hasDefaultArg()) {
+        llvm::raw_string_ostream Out(P.Default);
+        PVD->getDefaultArg()->printPretty(Out, nullptr, Policy);
+      }
+    }
+    if (FD->isVariadic()) {
+      HI.Parameters->emplace_back();
+      HI.Parameters->back().T = "...";
+    }
+  } else {
+    auto QT = getDeclType(D);
+    if (!QT.isNull()) {
+      HI.T.emplace();
+      llvm::raw_string_ostream OS(*HI.T);
+      QT.print(OS, std::move(Policy));
+    }
+  }
+
+  if (auto DefLoc = getDeclLoc(findNameLoc(D), D->getASTContext())) {
+    HI.Sym.PreferredDeclaration = *DefLoc;
+    if (getDefinition(D) == D)
+      HI.Sym.Definition = *DefLoc;
+  }
+  HI.Definition = getDefinitionLine(D);
+  return HI;
 }
 
 /// Generate a \p Hover object given the type \p T.
-static Hover getHoverContents(QualType T, ASTContext &ASTCtx) {
-  Hover H;
-  std::string TypeText;
-  llvm::raw_string_ostream OS(TypeText);
-  PrintingPolicy Policy = printingPolicyForDecls(ASTCtx.getPrintingPolicy());
-  T.print(OS, Policy);
-  OS.flush();
-  H.contents.value += TypeText;
-  return H;
+static HoverInfo getHoverContents(QualType T, ASTContext &ASTCtx) {
+  HoverInfo HI;
+  {
+    HI.T.emplace();
+    llvm::raw_string_ostream OS(*HI.T);
+    PrintingPolicy Policy = printingPolicyForDecls(ASTCtx.getPrintingPolicy());
+    T.print(OS, Policy);
+  }
+  HI.Sym.Name = *HI.T;
+  if (const TagDecl *TD = T.getTypePtr()->getAsTagDecl()) {
+    if (auto ScopedName = getScopeName(TD))
+      HI.ParentScope = std::move(*ScopedName);
+    HI.Scope = printQualifiedName(*TD);
+    HI.Kind = indexSymbolKindToSymbolKind(index::getSymbolInfo(TD).Kind);
+    // FIXME: Populate documentation
+    if (auto DefLoc = getDeclLoc(findNameLoc(TD), TD->getASTContext())) {
+      HI.Sym.PreferredDeclaration = *DefLoc;
+      if (getDefinition(TD) == TD)
+        HI.Sym.Definition = *DefLoc;
+    }
+    HI.Definition = getDefinitionLine(TD);
+  }
+  return HI;
 }
 
 /// Generate a \p Hover object given the macro \p MacroDecl.
-static Hover getHoverContents(MacroDecl Decl, ParsedAST &AST) {
+static HoverInfo getHoverContents(MacroDecl Decl, ParsedAST &AST) {
+  HoverInfo HI;
   SourceManager &SM = AST.getASTContext().getSourceManager();
-  std::string Definition = Decl.Name;
+  HI.Sym.Name = Decl.Name;
+  HI.Kind = indexSymbolKindToSymbolKind(
+      index::getSymbolInfoForMacro(*Decl.Info).Kind);
+  // FIXME: Populate documentation
 
   // Try to get the full definition, not just the name
   SourceLocation StartLoc = Decl.Info->getDefinitionLoc();
@@ -586,14 +749,15 @@
       unsigned StartOffset = SM.getFileOffset(StartLoc);
       unsigned EndOffset = SM.getFileOffset(EndLoc);
       if (EndOffset <= Buffer.size() && StartOffset < EndOffset)
-        Definition = Buffer.substr(StartOffset, EndOffset - StartOffset).str();
+        HI.Definition =
+            Buffer.substr(StartOffset, EndOffset - StartOffset).str();
     }
   }
-
-  Hover H;
-  H.contents.kind = MarkupKind::PlainText;
-  H.contents.value = "#define " + Definition;
-  return H;
+  if (auto DefLoc = getDeclLoc(StartLoc, AST.getASTContext())) {
+    HI.Sym.PreferredDeclaration = *DefLoc;
+    HI.Sym.Definition = *DefLoc;
+  }
+  return HI;
 }
 
 namespace {
@@ -708,7 +872,7 @@
   return V.getDeducedType();
 }
 
-llvm::Optional<Hover> getHover(ParsedAST &AST, Position Pos) {
+llvm::Optional<HoverInfo> getHover(ParsedAST &AST, Position Pos) {
   const SourceManager &SourceMgr = AST.getASTContext().getSourceManager();
   SourceLocation SourceLocationBeg =
       getBeginningOfIdentifier(AST, Pos, SourceMgr.getMainFileID());
@@ -748,7 +912,7 @@
   auto MainFileRefs = findRefs(Symbols.Decls, AST);
   for (const auto &Ref : MainFileRefs) {
     Location Result;
-    Result.range = getTokenRange(AST, Ref.Loc);
+    Result.range = getTokenRange(AST.getASTContext(), Ref.Loc);
     Result.uri = URIForFile::canonicalize(*MainFilePath, *MainFilePath);
     Results.push_back(std::move(Result));
   }
@@ -991,5 +1155,70 @@
   return Result;
 }
 
+Hover HoverInfo::render() const {
+  Hover H;
+  H.range = Sym.PreferredDeclaration.range;
+  H.contents.kind = MarkupKind::PlainText;
+  std::vector<std::string> Output;
+
+  if (!Scope.empty())
+    H.contents.value = llvm::formatv("Declared in {0}\n\n", Scope);
+
+  if (Kind == SymbolKind::String) {
+    // We use SymbolKind::String for macro kinds
+    Output.push_back("#define");
+    if (!Definition.empty())
+      Output.push_back(Definition);
+    else
+      Output.push_back(Sym.Name);
+  } else if (T || ReturnType) {
+    // Non-macros
+    if (TemplateParameters) {
+      Output.emplace_back();
+      llvm::raw_string_ostream OS(Output.back());
+      OS << "template <" << *TemplateParameters << '>';
+    }
+    if (T)
+      Output.push_back(*T);
+    else if (ReturnType)
+      Output.push_back(*ReturnType);
+
+    if (!Sym.Name.empty())
+      if (!T || !llvm::StringRef(*T).endswith(Sym.Name))
+        Output.push_back(Sym.Name);
+
+    if (Parameters) {
+      // We don't want space before parameters.
+      llvm::raw_string_ostream OS(Output.back());
+      OS << '(' << *Parameters << ')';
+    }
+  } else {
+    // Symbols without types, like namespaces.
+    Output.push_back(Definition);
+  }
+  H.contents.value += llvm::join(Output, " ");
+  return H;
+}
+
+llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
+                              const HoverInfo::Param &P) {
+  OS << P.T << ' ' << P.Name;
+  if (!P.Default.empty())
+    OS << " = " << P.Default;
+  return OS;
+}
+
+llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const HoverInfo &HI) {
+  OS << HI.Definition << '\n';
+  OS << HI.Documentation << '\n';
+  OS << HI.Parameters << '\n';
+  OS << HI.ReturnType << '\n';
+  OS << HI.Scope << '\n';
+  OS << HI.Sym << '\n';
+  OS << HI.T << '\n';
+  OS << HI.TemplateParameters << '\n';
+  return OS;
+}
+
 } // namespace clangd
 } // namespace clang
diff --git a/clang-tools-extra/clangd/unittests/XRefsTests.cpp b/clang-tools-extra/clangd/unittests/XRefsTests.cpp
--- a/clang-tools-extra/clangd/unittests/XRefsTests.cpp
+++ b/clang-tools-extra/clangd/unittests/XRefsTests.cpp
@@ -1185,7 +1185,9 @@
     auto AST = TU.build();
     if (auto H = getHover(AST, T.point())) {
       EXPECT_NE("", Test.ExpectedHover) << Test.Input;
-      EXPECT_EQ(H->contents.value, Test.ExpectedHover.str()) << Test.Input;
+      EXPECT_EQ(H->render().contents.value, Test.ExpectedHover.str())
+          << Test.Input << '\n'
+          << H;
     } else
       EXPECT_EQ("", Test.ExpectedHover.str()) << Test.Input;
   }