diff --git a/src/command_line.cc b/src/command_line.cc
index affff753..df72c8fe 100644
--- a/src/command_line.cc
+++ b/src/command_line.cc
@@ -343,6 +343,8 @@ void LaunchStdinLoop(Config* config,
         case IpcId::CqueryFileInfo:
         case IpcId::CqueryFreshenIndex:
         case IpcId::CqueryInheritanceHierarchy:
+        case IpcId::CqueryCallHierarchyInitial:
+        case IpcId::CqueryCallHierarchyExpand:
         case IpcId::CqueryCallTreeInitial:
         case IpcId::CqueryCallTreeExpand:
         case IpcId::CqueryMemberHierarchyInitial:
diff --git a/src/ipc.cc b/src/ipc.cc
index 0856d384..bb78dd97 100644
--- a/src/ipc.cc
+++ b/src/ipc.cc
@@ -72,6 +72,10 @@ const char* IpcIdToString(IpcId id) {
       return "$cquery/freshenIndex";
     case IpcId::CqueryInheritanceHierarchy:
       return "$cquery/inheritanceHierarchy";
+    case IpcId::CqueryCallHierarchyInitial:
+      return "$cquery/callHierarchyInitial";
+    case IpcId::CqueryCallHierarchyExpand:
+      return "$cquery/callHierarchyExpand";
     case IpcId::CqueryCallTreeInitial:
       return "$cquery/callTreeInitial";
     case IpcId::CqueryCallTreeExpand:
diff --git a/src/ipc.h b/src/ipc.h
index e902e0b8..dcae371a 100644
--- a/src/ipc.h
+++ b/src/ipc.h
@@ -49,6 +49,8 @@ enum class IpcId : int {
   CqueryFreshenIndex,
   // Messages used in tree views.
   CqueryInheritanceHierarchy,
+  CqueryCallHierarchyInitial,
+  CqueryCallHierarchyExpand,
   CqueryCallTreeInitial,
   CqueryCallTreeExpand,
   CqueryMemberHierarchyInitial,
diff --git a/src/messages/cquery_call_hierarchy.cc b/src/messages/cquery_call_hierarchy.cc
new file mode 100644
index 00000000..b3c6d189
--- /dev/null
+++ b/src/messages/cquery_call_hierarchy.cc
@@ -0,0 +1,210 @@
+#include "message_handler.h"
+#include "query_utils.h"
+#include "queue_manager.h"
+
+#include <loguru.hpp>
+
+namespace {
+struct Ipc_CqueryCallHierarchyInitial
+    : public RequestMessage<Ipc_CqueryCallHierarchyInitial> {
+  const static IpcId kIpcId = IpcId::CqueryCallHierarchyInitial;
+  struct Params {
+    lsTextDocumentIdentifier textDocument;
+    lsPosition position;
+    bool callee = false;
+    int levels = 1;
+  };
+  Params params;
+};
+MAKE_REFLECT_STRUCT(Ipc_CqueryCallHierarchyInitial::Params,
+                    textDocument,
+                    position,
+                    callee,
+                    levels);
+MAKE_REFLECT_STRUCT(Ipc_CqueryCallHierarchyInitial, id, params);
+REGISTER_IPC_MESSAGE(Ipc_CqueryCallHierarchyInitial);
+
+enum class CallType { Direct = 0, Base = 1, Derived = 2, All = 1 | 2 };
+MAKE_REFLECT_TYPE_PROXY(CallType);
+
+struct Ipc_CqueryCallHierarchyExpand
+    : public RequestMessage<Ipc_CqueryCallHierarchyExpand> {
+  const static IpcId kIpcId = IpcId::CqueryCallHierarchyExpand;
+  struct Params {
+    Maybe<QueryFuncId> id;
+    // true: callee tree; false: caller tree
+    bool callee = false;
+    int levels = 1;
+  };
+  Params params;
+};
+MAKE_REFLECT_STRUCT(Ipc_CqueryCallHierarchyExpand::Params, id, callee, levels);
+MAKE_REFLECT_STRUCT(Ipc_CqueryCallHierarchyExpand, id, params);
+REGISTER_IPC_MESSAGE(Ipc_CqueryCallHierarchyExpand);
+
+struct Out_CqueryCallHierarchy : public lsOutMessage<Out_CqueryCallHierarchy> {
+  struct Entry {
+    QueryFuncId id;
+    std::string_view name;
+    lsLocation location;
+    CallType callType = CallType::Direct;
+    int numChildren;
+    // Empty if the |levels| limit is reached.
+    std::vector<Entry> children;
+  };
+
+  lsRequestId id;
+  optional<Entry> result;
+};
+MAKE_REFLECT_STRUCT(Out_CqueryCallHierarchy::Entry,
+                    id,
+                    name,
+                    location,
+                    callType,
+                    numChildren,
+                    children);
+MAKE_REFLECT_STRUCT(Out_CqueryCallHierarchy, jsonrpc, id, result);
+
+void Expand(MessageHandler* m,
+            Out_CqueryCallHierarchy::Entry* entry,
+            bool callee,
+            int levels) {
+  const QueryFunc& func = m->db->funcs[entry->id.id];
+  const QueryFunc::Def* def = func.AnyDef();
+  entry->numChildren = 0;
+  if (!def)
+    return;
+  if (def->spell) {
+    if (optional<lsLocation> loc =
+        GetLsLocation(m->db, m->working_files, *def->spell))
+      entry->location = *loc;
+  }
+  auto handle = [&](Use use, CallType call_type) {
+    QueryFunc& rel_func = m->db->GetFunc(use);
+    const QueryFunc::Def* rel_def = rel_func.AnyDef();
+    if (!rel_def)
+      return;
+    if (optional<lsLocation> loc =
+            GetLsLocation(m->db, m->working_files, use)) {
+      entry->numChildren++;
+      if (levels > 0) {
+        Out_CqueryCallHierarchy::Entry entry1;
+        entry1.id = QueryFuncId(use.id);
+        entry1.name = rel_def->ShortName();
+        entry1.location = *loc;
+        entry1.callType = call_type;
+        Expand(m, &entry1, callee, levels - 1);
+        entry->children.push_back(std::move(entry1));
+      }
+    }
+  };
+  auto handle_uses = [&](const QueryFunc& func, CallType call_type) {
+    if (callee) {
+      if (const auto* def = func.AnyDef())
+        for (SymbolRef ref : def->callees)
+          if (ref.kind == SymbolKind::Func)
+            handle(Use(ref.range, ref.id, ref.kind, ref.role, def->file), call_type);
+    } else {
+      for (Use use : func.uses)
+        if (use.kind == SymbolKind::Func)
+          handle(use, call_type);
+    }
+  };
+
+  std::unordered_set<Usr> seen;
+  std::vector<const QueryFunc*> stack;
+  handle_uses(func, CallType::Direct);
+
+  // Callers/callees of base functions.
+  stack.push_back(&func);
+  while (stack.size()) {
+    const QueryFunc& func1 = *stack.back();
+    stack.pop_back();
+    if (auto* def1 = func1.AnyDef()) {
+      EachDefinedEntity(m->db->funcs, def1->base, [&](QueryFunc& func2) {
+        if (seen.count(func2.usr)) {
+          seen.insert(func2.usr);
+          stack.push_back(&func2);
+          handle_uses(func2, CallType::Base);
+        }
+      });
+    }
+  }
+
+  // Callers/callees of derived functions.
+  stack.push_back(&func);
+  while (stack.size()) {
+    const QueryFunc& func1 = *stack.back();
+    stack.pop_back();
+    EachDefinedEntity(m->db->funcs, func1.derived, [&](QueryFunc& func2) {
+      if (seen.count(func2.usr)) {
+        seen.insert(func2.usr);
+        stack.push_back(&func2);
+        handle_uses(func2, CallType::Derived);
+      }
+    });
+  }
+}
+
+struct CqueryCallHierarchyInitialHandler
+    : BaseMessageHandler<Ipc_CqueryCallHierarchyInitial> {
+  optional<Out_CqueryCallHierarchy::Entry> BuildInitial(QueryFuncId root_id,
+                                                        bool callee,
+                                                        int levels) {
+    const auto* def = db->funcs[root_id.id].AnyDef();
+    if (!def)
+      return {};
+
+    Out_CqueryCallHierarchy::Entry entry;
+    entry.id = root_id;
+    entry.name = def->ShortName();
+    Expand(this, &entry, callee, levels);
+    return entry;
+  }
+
+  void Run(Ipc_CqueryCallHierarchyInitial* request) override {
+    QueryFile* file;
+    const auto& params = request->params;
+    if (!FindFileOrFail(db, project, request->id,
+                        params.textDocument.uri.GetPath(), &file))
+      return;
+
+    WorkingFile* working_file =
+        working_files->GetFileByFilename(file->def->path);
+    Out_CqueryCallHierarchy out;
+    out.id = request->id;
+
+    for (SymbolRef sym :
+         FindSymbolsAtLocation(working_file, file, params.position)) {
+      if (sym.kind == SymbolKind::Func) {
+        out.result =
+            BuildInitial(QueryFuncId(sym.id), params.callee, params.levels);
+        break;
+      }
+    }
+
+    QueueManager::WriteStdout(IpcId::CqueryCallHierarchyInitial, out);
+  }
+};
+REGISTER_MESSAGE_HANDLER(CqueryCallHierarchyInitialHandler);
+
+struct CqueryCallHierarchyExpandHandler
+    : BaseMessageHandler<Ipc_CqueryCallHierarchyExpand> {
+  void Run(Ipc_CqueryCallHierarchyExpand* request) override {
+    const auto& params = request->params;
+    Out_CqueryCallHierarchy out;
+    out.id = request->id;
+    if (params.id) {
+      Out_CqueryCallHierarchy::Entry entry;
+      entry.id = *params.id;
+      // entry.name is empty and it is known by the client.
+      if (entry.id.id < db->funcs.size())
+        Expand(this, &entry, params.callee, params.levels);
+      out.result = std::move(entry);
+    }
+
+    QueueManager::WriteStdout(IpcId::CqueryCallHierarchyExpand, out);
+  }
+};
+REGISTER_MESSAGE_HANDLER(CqueryCallHierarchyExpandHandler);
+}  // namespace
diff --git a/src/messages/cquery_member_hierarchy.cc b/src/messages/cquery_member_hierarchy.cc
index 3b4302bf..858991b3 100644
--- a/src/messages/cquery_member_hierarchy.cc
+++ b/src/messages/cquery_member_hierarchy.cc
@@ -39,7 +39,10 @@ struct Out_CqueryMemberHierarchy
   struct Entry {
     QueryTypeId id;
     std::string_view name;
+    std::string_view field_name;
     lsLocation location;
+    // For unexpanded nodes, this is an upper bound because some entities may be
+    // undefined. If it is 0, there are no members.
     int numChildren;
     // Empty if the |levels| limit is reached.
     std::vector<Entry> children;
@@ -50,6 +53,7 @@ struct Out_CqueryMemberHierarchy
 MAKE_REFLECT_STRUCT(Out_CqueryMemberHierarchy::Entry,
                     id,
                     name,
+                    field_name,
                     location,
                     numChildren,
                     children);
@@ -61,6 +65,7 @@ void Expand(MessageHandler* m, Out_CqueryMemberHierarchy::Entry* entry, int leve
     entry->numChildren = 0;
     return;
   }
+  entry->name = def->ShortName();
   if (def->spell) {
     if (optional<lsLocation> loc =
         GetLsLocation(m->db, m->working_files, *def->spell))
@@ -71,11 +76,12 @@ void Expand(MessageHandler* m, Out_CqueryMemberHierarchy::Entry* entry, int leve
     EachDefinedEntity(m->db->vars, def->vars, [&](QueryVar& var) {
         const QueryVar::Def* def1 = var.AnyDef();
         Out_CqueryMemberHierarchy::Entry entry1;
-        entry1.name = def1->ShortName();
         entry1.id = def1->type ? *def1->type : QueryTypeId();
+        entry1.field_name = def1->ShortName();
         Expand(m, &entry1, levels - 1);
         entry->children.push_back(std::move(entry1));
       });
+    entry->numChildren = int(entry->children.size());
   }
 }
 
@@ -89,7 +95,6 @@ struct CqueryMemberHierarchyInitialHandler
 
     Out_CqueryMemberHierarchy::Entry entry;
     entry.id = root_id;
-    entry.name = def->ShortName();
     Expand(this, &entry, levels);
     return entry;
   }