diff --git a/toolchain/check/handle_class.cpp b/toolchain/check/handle_class.cpp
index 8e2d1591c316..02437612fd4b 100644
--- a/toolchain/check/handle_class.cpp
+++ b/toolchain/check/handle_class.cpp
@@ -443,6 +443,15 @@ auto HandleParseNode(Context& context, Parse::BaseDeclId node_id) -> bool {
   return true;
 }
 
+auto HandleParseNode(Context& context, Parse::FriendIntroducerId node_id)
+    -> bool {
+  return context.TODO(node_id, "friend decl not supported in check");
+}
+
+auto HandleParseNode(Context& context, Parse::FriendDeclId node_id) -> bool {
+  return context.TODO(node_id, "friend decl not supported in check");
+}
+
 auto HandleParseNode(Context& context, Parse::ClassDefinitionId node_id)
     -> bool {
   auto class_id =
diff --git a/toolchain/check/node_stack.h b/toolchain/check/node_stack.h
index b1c630231108..da469ae30c79 100644
--- a/toolchain/check/node_stack.h
+++ b/toolchain/check/node_stack.h
@@ -507,6 +507,7 @@ class NodeStack {
       case Parse::NodeKind::Forall:
       case Parse::NodeKind::FormLiteralKeyword:
       case Parse::NodeKind::FormLiteralOpenParen:
+      case Parse::NodeKind::FriendIntroducer:
       case Parse::NodeKind::IdentifierNameQualifierWithParams:
       case Parse::NodeKind::IdentifierNameQualifierWithoutParams:
       case Parse::NodeKind::IdentifierPackageName:
diff --git a/toolchain/diagnostics/kind.def b/toolchain/diagnostics/kind.def
index 0818cf79aec8..de80e73f9854 100644
--- a/toolchain/diagnostics/kind.def
+++ b/toolchain/diagnostics/kind.def
@@ -200,6 +200,7 @@ CARBON_DIAGNOSTIC_KIND(ExpectedAssociatedConstantIdentifier)
 CARBON_DIAGNOSTIC_KIND(ExpectedAssociatedConstantColon)
 CARBON_DIAGNOSTIC_KIND(PhaseKeywordInAssociatedConstant)
 CARBON_DIAGNOSTIC_KIND(RequireExpectedImpls)
+CARBON_DIAGNOSTIC_KIND(ExpectedIdentifierForFriend)
 
 // Alias diagnostics.
 CARBON_DIAGNOSTIC_KIND(ExpectedAliasInitializer)
diff --git a/toolchain/parse/handle_decl_scope_loop.cpp b/toolchain/parse/handle_decl_scope_loop.cpp
index 233c5bbcd10c..bde08bbd8426 100644
--- a/toolchain/parse/handle_decl_scope_loop.cpp
+++ b/toolchain/parse/handle_decl_scope_loop.cpp
@@ -123,6 +123,8 @@ static constexpr auto DeclIntroducers = [] {
   set(Lex::TokenKind::Export, NodeKind::ExportIntroducer,
       StateKind::ExportName);
   // TODO: Treat `extend` as a declaration introducer.
+  set(Lex::TokenKind::Friend, NodeKind::FriendIntroducer,
+      StateKind::FriendDecl);
   set(Lex::TokenKind::Fn, NodeKind::FunctionIntroducer,
       StateKind::FunctionIntroducer);
   set(Lex::TokenKind::Impl, NodeKind::ImplIntroducer,
diff --git a/toolchain/parse/handle_friend.cpp b/toolchain/parse/handle_friend.cpp
new file mode 100644
index 000000000000..23df932082b2
--- /dev/null
+++ b/toolchain/parse/handle_friend.cpp
@@ -0,0 +1,34 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#include "toolchain/parse/context.h"
+#include "toolchain/parse/handle.h"
+
+namespace Carbon::Parse {
+
+// Handles processing of a complete `friend X` declaration.
+auto HandleFriendDecl(Context& context) -> void {
+  auto state = context.PopState();
+  if (state.has_error) {
+    context.RecoverFromDeclError(state, NodeKind::FriendDecl,
+                                 /*skip_past_likely_end=*/true);
+    return;
+  }
+
+  if (!context.ConsumeAndAddLeafNodeIf(Lex::TokenKind::Identifier,
+                                       NodeKind::IdentifierNameExpr)) {
+    state.has_error = true;
+    CARBON_DIAGNOSTIC(ExpectedIdentifierForFriend, Error,
+                      "expected identifier for friend declaration");
+    context.emitter().Emit(*context.position(), ExpectedIdentifierForFriend);
+    context.RecoverFromDeclError(state, NodeKind::FriendDecl,
+                                 /*skip_past_likely_end=*/true);
+    return;
+  }
+  context.AddNodeExpectingDeclSemi(state, NodeKind::FriendDecl,
+                                   Lex::TokenKind::Friend,
+                                   /*is_def_allowed=*/false);
+}
+
+}  // namespace Carbon::Parse
diff --git a/toolchain/parse/node_kind.def b/toolchain/parse/node_kind.def
index 6b982d6042f8..bc86ef7448da 100644
--- a/toolchain/parse/node_kind.def
+++ b/toolchain/parse/node_kind.def
@@ -439,6 +439,9 @@ CARBON_PARSE_NODE_KIND_DECLARATION(BaseIntroducer)
 CARBON_PARSE_NODE_KIND_DECLARATION(BaseColon)
 CARBON_PARSE_NODE_KIND_DECLARATION(BaseDecl)
 
+CARBON_PARSE_NODE_KIND_DECLARATION(FriendIntroducer)
+CARBON_PARSE_NODE_KIND_DECLARATION(FriendDecl)
+
 CARBON_PARSE_NODE_KIND_DECLARATION(InterfaceIntroducer)
 CARBON_PARSE_NODE_KIND_DECLARATION(InterfaceDefinitionStart)
 CARBON_PARSE_NODE_KIND_DECLARATION(InterfaceDefinition)
diff --git a/toolchain/parse/state.def b/toolchain/parse/state.def
index 286cf58c9157..2bc83e61156d 100644
--- a/toolchain/parse/state.def
+++ b/toolchain/parse/state.def
@@ -378,6 +378,10 @@ CARBON_PARSE_STATE(DeclNameAndParamsAfterParams)
 // ^~
 //   1. FunctionIntroducer
 //
+// friend ...
+// ^~~~~~
+//   1. FriendDecl
+//
 // impl ...
 // ^~~~
 //   1. ImplAfterIntroducer
@@ -753,6 +757,15 @@ CARBON_PARSE_STATE(WhereFinish)
 //   (state done)
 CARBON_PARSE_STATE(ExprStatementFinish)
 
+// Handles a `friend` declaration.
+//
+// friend <identifier> ;
+//        ^~~~~~~~~~~~~~
+// friend ??? ;
+//        ^~~~~
+//   (state done)
+CARBON_PARSE_STATE(FriendDecl)
+
 // Handles a function's introducer.
 //
 // fn ...
diff --git a/toolchain/parse/testdata/class/friend.carbon b/toolchain/parse/testdata/class/friend.carbon
new file mode 100644
index 000000000000..4b2649e3bab2
--- /dev/null
+++ b/toolchain/parse/testdata/class/friend.carbon
@@ -0,0 +1,126 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/parse/testdata/class/friend.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/parse/testdata/class/friend.carbon
+
+// --- friend.carbon
+
+class Foo {
+  friend Bar;
+}
+
+// --- fail_todo_qualified.carbon
+
+class Baz {
+  // CHECK:STDERR: fail_todo_qualified.carbon:[[@LINE+4]]:11: error: `friend` declarations must end with a `;` [ExpectedDeclSemi]
+  // CHECK:STDERR:   friend P.Q;
+  // CHECK:STDERR:           ^
+  // CHECK:STDERR:
+  friend P.Q;
+}
+
+// --- fail_bad_syntax.carbon
+
+class A {
+  // CHECK:STDERR: fail_bad_syntax.carbon:[[@LINE+4]]:9: error: expected identifier for friend declaration [ExpectedIdentifierForFriend]
+  // CHECK:STDERR:   friend;
+  // CHECK:STDERR:         ^
+  // CHECK:STDERR:
+  friend;
+}
+
+class B {
+  // CHECK:STDERR: fail_bad_syntax.carbon:[[@LINE+4]]:12: error: `friend` declarations must end with a `;` [ExpectedDeclSemi]
+  // CHECK:STDERR:   friend X extra_token;
+  // CHECK:STDERR:            ^~~~~~~~~~~
+  // CHECK:STDERR:
+  friend X extra_token;
+}
+
+class C {
+  friend
+// CHECK:STDERR: fail_bad_syntax.carbon:[[@LINE+4]]:1: error: expected identifier for friend declaration [ExpectedIdentifierForFriend]
+// CHECK:STDERR: }
+// CHECK:STDERR: ^
+// CHECK:STDERR:
+}
+
+class D {
+  friend X
+// CHECK:STDERR: fail_bad_syntax.carbon:[[@LINE+4]]:1: error: `friend` declarations must end with a `;` [ExpectedDeclSemi]
+// CHECK:STDERR: }
+// CHECK:STDERR: ^
+// CHECK:STDERR:
+}
+
+class E {
+  // CHECK:STDERR: fail_bad_syntax.carbon:[[@LINE+4]]:10: error: expected identifier for friend declaration [ExpectedIdentifierForFriend]
+  // CHECK:STDERR:   friend class;
+  // CHECK:STDERR:          ^~~~~
+  // CHECK:STDERR:
+  friend class;
+}
+
+// CHECK:STDOUT: - filename: friend.carbon
+// CHECK:STDOUT:   ╭─FileStart ''
+// CHECK:STDOUT:   │   ╭─ClassIntroducer 'class'
+// CHECK:STDOUT:   │   ├─IdentifierNameNotBeforeSignature 'Foo'
+// CHECK:STDOUT:   │ ╭─ClassDefinitionStart '{'
+// CHECK:STDOUT:   │ │ ╭─FriendIntroducer 'friend'
+// CHECK:STDOUT:   │ │ ├─IdentifierNameExpr 'Bar'
+// CHECK:STDOUT:   │ ├─FriendDecl ';'
+// CHECK:STDOUT:   ├─ClassDefinition '}'
+// CHECK:STDOUT:   ├─FileEnd ''
+// CHECK:STDOUT:   (root)
+// CHECK:STDOUT: - filename: fail_todo_qualified.carbon
+// CHECK:STDOUT:   ╭─FileStart ''
+// CHECK:STDOUT:   │   ╭─ClassIntroducer 'class'
+// CHECK:STDOUT:   │   ├─IdentifierNameNotBeforeSignature 'Baz'
+// CHECK:STDOUT:   │ ╭─ClassDefinitionStart '{'
+// CHECK:STDOUT:   │ │ ╭─FriendIntroducer 'friend'
+// CHECK:STDOUT:   │ │ ├─IdentifierNameExpr 'P'
+// CHECK:STDOUT:   │ ├─FriendDecl ';' has_error
+// CHECK:STDOUT:   ├─ClassDefinition '}'
+// CHECK:STDOUT:   ├─FileEnd ''
+// CHECK:STDOUT:   (root)
+// CHECK:STDOUT: - filename: fail_bad_syntax.carbon
+// CHECK:STDOUT:   ╭─FileStart ''
+// CHECK:STDOUT:   │   ╭─ClassIntroducer 'class'
+// CHECK:STDOUT:   │   ├─IdentifierNameNotBeforeSignature 'A'
+// CHECK:STDOUT:   │ ╭─ClassDefinitionStart '{'
+// CHECK:STDOUT:   │ │ ╭─FriendIntroducer 'friend'
+// CHECK:STDOUT:   │ ├─FriendDecl ';' has_error
+// CHECK:STDOUT:   ├─ClassDefinition '}'
+// CHECK:STDOUT:   │   ╭─ClassIntroducer 'class'
+// CHECK:STDOUT:   │   ├─IdentifierNameNotBeforeSignature 'B'
+// CHECK:STDOUT:   │ ╭─ClassDefinitionStart '{'
+// CHECK:STDOUT:   │ │ ╭─FriendIntroducer 'friend'
+// CHECK:STDOUT:   │ │ ├─IdentifierNameExpr 'X'
+// CHECK:STDOUT:   │ ├─FriendDecl ';' has_error
+// CHECK:STDOUT:   ├─ClassDefinition '}'
+// CHECK:STDOUT:   │   ╭─ClassIntroducer 'class'
+// CHECK:STDOUT:   │   ├─IdentifierNameNotBeforeSignature 'C'
+// CHECK:STDOUT:   │ ╭─ClassDefinitionStart '{'
+// CHECK:STDOUT:   │ │ ╭─FriendIntroducer 'friend'
+// CHECK:STDOUT:   │ ├─FriendDecl 'friend' has_error
+// CHECK:STDOUT:   ├─ClassDefinition '}'
+// CHECK:STDOUT:   │   ╭─ClassIntroducer 'class'
+// CHECK:STDOUT:   │   ├─IdentifierNameNotBeforeSignature 'D'
+// CHECK:STDOUT:   │ ╭─ClassDefinitionStart '{'
+// CHECK:STDOUT:   │ │ ╭─FriendIntroducer 'friend'
+// CHECK:STDOUT:   │ │ ├─IdentifierNameExpr 'X'
+// CHECK:STDOUT:   │ ├─FriendDecl 'X' has_error
+// CHECK:STDOUT:   ├─ClassDefinition '}'
+// CHECK:STDOUT:   │   ╭─ClassIntroducer 'class'
+// CHECK:STDOUT:   │   ├─IdentifierNameNotBeforeSignature 'E'
+// CHECK:STDOUT:   │ ╭─ClassDefinitionStart '{'
+// CHECK:STDOUT:   │ │ ╭─FriendIntroducer 'friend'
+// CHECK:STDOUT:   │ ├─FriendDecl ';' has_error
+// CHECK:STDOUT:   ├─ClassDefinition '}'
+// CHECK:STDOUT:   ├─FileEnd ''
+// CHECK:STDOUT:   (root)
diff --git a/toolchain/parse/typed_nodes.h b/toolchain/parse/typed_nodes.h
index 7481f442d682..55c46b6bd393 100644
--- a/toolchain/parse/typed_nodes.h
+++ b/toolchain/parse/typed_nodes.h
@@ -1650,6 +1650,25 @@ struct BaseDecl {
   Lex::SemiTokenIndex token;
 };
 
+// Friend declaration
+// ------------------
+
+using FriendIntroducer =
+    LeafNode<NodeKind::FriendIntroducer, Lex::FriendTokenIndex>;
+
+struct FriendDecl {
+  static constexpr auto Kind = NodeKind::FriendDecl.Define(
+      {.category = NodeCategory::Decl, .bracketed_by = FriendIntroducer::Kind});
+
+  FriendIntroducerId introducer;
+
+  // TODO: figure out the more general syntax for the name part of a friend
+  // declaration.
+  IdentifierNameExprId name;
+
+  Lex::SemiTokenIndex token;
+};
+
 // Interface declarations and definitions
 // --------------------------------------