diff --git a/include/swift/AST/KnownIdentifiers.def b/include/swift/AST/KnownIdentifiers.def
index 9f628ac87606..e535d333cdb7 100644
--- a/include/swift/AST/KnownIdentifiers.def
+++ b/include/swift/AST/KnownIdentifiers.def
@@ -126,7 +126,6 @@ IDENTIFIER(objectForKeyedSubscript)
 IDENTIFIER(ObjectiveC)
 IDENTIFIER_(ObjectiveCType)
 IDENTIFIER(Observation)
-IDENTIFIER_WITH_NAME(Observation_, "_Observation")
 IDENTIFIER(oldValue)
 IDENTIFIER(Optional)
 IDENTIFIER_(OptionalNilComparisonType)
diff --git a/lib/AST/NameLookup.cpp b/lib/AST/NameLookup.cpp
index a405095cc1f0..5ce151a3a7af 100644
--- a/lib/AST/NameLookup.cpp
+++ b/lib/AST/NameLookup.cpp
@@ -680,11 +680,8 @@ static void recordShadowedDeclsAfterTypeMatch(
         }
       }
 
-      // Next, prefer any other module over the (_)Observation module.
-      auto obsModule = ctx.getLoadedModule(ctx.Id_Observation);
-      if (!obsModule)
-        obsModule = ctx.getLoadedModule(ctx.Id_Observation_);
-      if (obsModule) {
+      // Next, prefer any other module over the Observation module.
+      if (auto obsModule = ctx.getLoadedModule(ctx.Id_Observation)) {
         if ((firstModule == obsModule) != (secondModule == obsModule)) {
           // If second module is (_)Observation, then it is shadowed by
           // first.
diff --git a/lib/Macros/Sources/ObservationMacros/ObservableMacro.swift b/lib/Macros/Sources/ObservationMacros/ObservableMacro.swift
index 8ed72c34d369..e242b386cc23 100644
--- a/lib/Macros/Sources/ObservationMacros/ObservableMacro.swift
+++ b/lib/Macros/Sources/ObservationMacros/ObservableMacro.swift
@@ -17,7 +17,7 @@ import SwiftSyntaxMacros
 @_implementationOnly import SwiftSyntaxBuilder
 
 public struct ObservableMacro {
-  static let moduleName = "_Observation"
+  static let moduleName = "Observation"
 
   static let conformanceName = "Observable"
   static var qualifiedConformanceName: String {
diff --git a/stdlib/public/Observation/Sources/Observation/CMakeLists.txt b/stdlib/public/Observation/Sources/Observation/CMakeLists.txt
index afe1ffb3b30f..9dc261e84b60 100644
--- a/stdlib/public/Observation/Sources/Observation/CMakeLists.txt
+++ b/stdlib/public/Observation/Sources/Observation/CMakeLists.txt
@@ -12,7 +12,7 @@
 
 list(APPEND swift_runtime_library_compile_flags -I${SWIFT_SOURCE_DIR}/stdlib/include -I${SWIFT_SOURCE_DIR}/include)
 
-add_swift_target_library(swift_Observation ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
+add_swift_target_library(swiftObservation ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
   Locking.cpp
   Locking.swift
   Observable.swift
diff --git a/test/ModuleInterface/Observable.swift b/test/ModuleInterface/Observable.swift
index e510c8ffab3d..173fc615d2b4 100644
--- a/test/ModuleInterface/Observable.swift
+++ b/test/ModuleInterface/Observable.swift
@@ -9,7 +9,7 @@
 // REQUIRES: swift_swift_parser
 // REQUIRES: observation
 
-import _Observation
+import Observation
 
 // CHECK-NOT: @Observable
 // CHECK-NOT: @ObservationIgnored
diff --git a/test/NameLookup/Inputs/ReexportsObservation.swift b/test/NameLookup/Inputs/ReexportsObservation.swift
index daf9b064b8e5..f9bca73a6635 100644
--- a/test/NameLookup/Inputs/ReexportsObservation.swift
+++ b/test/NameLookup/Inputs/ReexportsObservation.swift
@@ -1,2 +1,2 @@
-@_exported import _Observation
+@_exported import Observation
 
diff --git a/test/NameLookup/observable_shadowing.swift b/test/NameLookup/observable_shadowing.swift
index 7472cf602532..6260480d0643 100644
--- a/test/NameLookup/observable_shadowing.swift
+++ b/test/NameLookup/observable_shadowing.swift
@@ -11,7 +11,7 @@ import HasObservable
 #if VIA_REEXPORT
 import ReexportsObservation
 #else
-import _Observation
+import Observation
 #endif
 
 func foo() -> Observable<Int> {
diff --git a/test/stdlib/Observation/Observable.swift b/test/stdlib/Observation/Observable.swift
index 89a33cd4630f..c816d2b5ec54 100644
--- a/test/stdlib/Observation/Observable.swift
+++ b/test/stdlib/Observation/Observable.swift
@@ -10,7 +10,7 @@
 // REQUIRES: objc_interop
 
 import StdlibUnittest
-import _Observation
+import Observation
 
 @usableFromInline
 @inline(never)
diff --git a/test/stdlib/Observation/ObservableDidSetWillSet.swift b/test/stdlib/Observation/ObservableDidSetWillSet.swift
index 6004bdc56ce4..e7358fb8af66 100644
--- a/test/stdlib/Observation/ObservableDidSetWillSet.swift
+++ b/test/stdlib/Observation/ObservableDidSetWillSet.swift
@@ -11,7 +11,7 @@
 // UNSUPPORTED: use_os_stdlib
 // UNSUPPORTED: back_deployment_runtime
 
-import _Observation
+import Observation
 
 @Observable
 public class Model {