diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 76dfa5d3aa5fd..770e1bb91894b 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -1,13 +1,33 @@
 # Lines starting with '#' are comments.
-# Each line is a file pattern followed by one or more owners.
+# Each line is a case-sensitive file pattern followed by one or more owners.
 # Order is important. The last matching pattern has the most precedence.
+# More information: https://docs.github.com/en/articles/about-code-owners
 
-# Owners of ASTGen
-lib/ASTGen @zoecarver @CodaFi
+# .github
+/.github/                         @shahmishal
+/.github/CODEOWNERS               @AnthonyLatsis @shahmishal
+/.github/ISSUE_TEMPLATE/          @AnthonyLatsis @hborla @LucianoPAlmeida @shahmishal @xedin
+/.github/PULL_REQUEST_TEMPLATE.md @AnthonyLatsis @hborla @LucianoPAlmeida @shahmishal @xedin
+
+# docs
+/docs/HowToGuides/ @AnthonyLatsis @LucianoPAlmeida @xedin
+/docs/Generics/    @slavapestov
+/docs/Generics.rst @slavapestov
+
+# Standard Library
+# TODO: /stdlib/
+/stdlib/public/Cxx/        @zoecarver @hyp @egorzhdan
+/stdlib/public/Distributed/ @ktoso
+/stdlib/public/Windows/    @compnerd
+# TODO: /*test/stdlib/
+# TODO: /unittests/stdlib/
+
+# ASTGen
+/lib/ASTGen/  @zoecarver @CodaFi
+/test/ASTGen/ @zoecarver @CodaFi
 
 # Dependency scanning
 include/swift/DependencyScan                 @artemcm
-lib/AST/ModuleLoader.cpp                     @artemcm
 lib/DependencyScan                           @artemcm
 lib/Frontend/ModuleInterfaceLoader.cpp       @artemcm
 lib/Serialization/SerializedModuleLoader.cpp @artemcm
@@ -19,9 +39,10 @@ lib/Driver           @artemcm
 test/Driver          @artemcm
 
 # Owners of the parser
-include/swift/Parse @ahoppen @bnbarham @CodaFi @DougGregor @rintaro
-lib/Parse           @ahoppen @bnbarham @CodaFi @DougGregor @rintaro
-test/Parse          @ahoppen @bnbarham @CodaFi @DougGregor @rintaro
+/include/swift/Parse/ @ahoppen @bnbarham @CodaFi @DougGregor @rintaro
+/lib/Parse/           @ahoppen @bnbarham @CodaFi @DougGregor @rintaro
+/*test/Parse/         @ahoppen @bnbarham @CodaFi @DougGregor @rintaro
+/unittests/Parse/     @ahoppen @bnbarham @CodaFi @DougGregor @rintaro
 
 SwiftCompilerSources @eeckstein
 
@@ -30,7 +51,6 @@ include/swift/ClangImporter @zoecarver @hyp @egorzhdan
 include/swift/PrintAsClang  @zoecarver @hyp @egorzhdan
 lib/ClangImporter           @zoecarver @hyp @egorzhdan
 lib/PrintAsClang            @zoecarver @hyp @egorzhdan
-stdlib/public/Cxx           @zoecarver @hyp @egorzhdan
 test/Interop                @zoecarver @hyp @egorzhdan
 
 # Threading implementation
@@ -40,5 +60,83 @@ lib/Threading           @al45tair
 # Windows support
 cmake/**/*Windows*    @compnerd
 lib/Basic/Windows     @compnerd
-stdlib/public/Windows @compnerd
 utils/*windows*       @compnerd
+
+# AST
+/include/swift/AST/               @hborla @slavapestov @xedin
+/include/swift/AST/*Conformance*  @slavapestov
+/include/swift/AST/*Distributed*  @ktoso
+/include/swift/AST/Evaluator*     @CodaFi @slavapestov
+/include/swift/AST/*Generic*      @hborla @slavapestov
+/include/swift/AST/*Protocol*     @hborla @slavapestov
+/include/swift/AST/*Requirement*  @hborla @slavapestov
+/include/swift/AST/*Substitution* @slavapestov
+/lib/AST/                         @hborla @slavapestov @xedin
+/lib/AST/*Conformance*            @slavapestov
+/lib/AST/Evaluator*               @CodaFi @slavapestov
+/lib/AST/*Generic*                @hborla @slavapestov
+/lib/AST/ModuleLoader.cpp         @artemcm
+/lib/AST/*Requirement*            @hborla @slavapestov
+/lib/AST/RequirementMachine/      @slavapestov
+/lib/AST/*Substitution            @slavapestov
+/unittests/AST/                   @hborla @slavapestov @xedin
+/unittests/AST/*Evaluator*        @CodaFi @slavapestov
+
+# Sema
+/include/swift/Sema/                     @hborla @slavapestov @xedin
+/include/swift/Sema/Constraint*          @hborla @xedin
+/include/swift/Sema/CS*                  @hborla @xedin
+/lib/Sema/                               @hborla @slavapestov @xedin
+/lib/Sema/Constraint*                    @hborla @xedin
+/lib/Sema/CS*                            @hborla @xedin
+/lib/Sema/CodeSynthesisDistributed*      @hborla @ktoso
+/lib/Sema/DerivedConformance*            @slavapestov
+/lib/Sema/DerivedConformanceDistributed* @ktoso @slavapestov
+/lib/Sema/TypeCheckDistributed*          @hborla @ktoso @xedin
+/lib/Sema/TypeCheckType*                 @AnthonyLatsis @hborla @slavapestov @xedin
+/lib/Sema/TypeCheckProtocol*             @AnthonyLatsis @hborla @slavapestov
+/test/Constraints/                       @hborla @xedin
+/test/decl/                              @hborla @slavapestov
+/test/decl/protocol/                     @AnthonyLatsis @hborla @slavapestov
+# FIXME: This file could have a dedicated directory.
+/test/decl/protocol/special/DistributedActor.swift  @ktoso
+# FIXME: Should there be a 'Sema' folder under 'Distributed'? Or perhaps it
+# should be the other way around, i.e 'Sema/Distributed', 'SILGen/Distributed',
+# etc.?
+/test/Distributed/*                      @ktoso
+# FIXME: Is there a better way to structure this high-level 'Inputs' dir.? We
+# want only the Sema bits here.
+/test/Distributed/Inputs/                @ktoso
+/test/expr/                              @hborla @slavapestov @xedin
+/test/Generics/                          @hborla @slavapestov
+/test/Sema/                              @hborla @slavapestov @xedin
+/test/stmt/                              @hborla @xedin
+/test/type/                              @hborla @slavapestov @xedin
+/validation-test/Sema/                   @hborla @slavapestov @xedin
+/unittests/Sema/                         @hborla @xedin
+
+# SIL/SILGen
+# TODO: /include/swift/SIL/
+# TODO: /lib/SIL/
+# TODO: /lib/SILGen/
+/lib/SILGen/*Distributed* @ktoso
+/test/Distributed/SIL/    @ktoso
+# TODO: /*test/SIL/
+# TODO: /*test/SILGen/
+# TODO: /unittests/SIL/
+
+# SILOptimizer
+# TODO: /include/swift/SILOptimizer/
+/include/swift/SILOptimizer/Utils/Distributed* @ktoso
+# TODO: /lib/SILOptimizer/
+/lib/SILOptimizer/Utils/Distributed*           @ktoso
+# TODO: /*test/SILOptimizer/
+
+# IRGen
+# TODO: /include/swift/IRGen/
+# TODO: /lib/IRGen/
+/lib/IRGen/*Distributed* @ktoso
+# TODO: /*test/IRGen/
+
+# TODO: Find a better place for this entry.
+/test/Distributed/Runtime @ktoso