diff --git a/packages/react-native/scripts/cocoapods/__tests__/spm-test.rb b/packages/react-native/scripts/cocoapods/__tests__/spm-test.rb
new file mode 100644
index 000000000000..89a308293c37
--- /dev/null
+++ b/packages/react-native/scripts/cocoapods/__tests__/spm-test.rb
@@ -0,0 +1,100 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+require "test/unit"
+require "fileutils"
+require "cocoapods"
+require_relative "../spm.rb"
+
+# These tests exercise the real `Pod::Project` UUID machinery (via the
+# `xcodeproj`/`cocoapods` gems) because the bug they guard against is emergent
+# from how `Pod::Project` hands out UUIDs, and cannot be observed against a mock.
+class SPMTests < Test::Unit::TestCase
+  PodSpecStub = Struct.new(:name)
+  InstallerStub = Struct.new(:pods_project)
+
+  POD_NAME = "ReactNativeEnrichedMarkdown"
+  TMP_DIR = File.join(Dir.tmpdir, "rn-spm-test")
+
+  def setup
+    FileUtils.rm_rf(TMP_DIR)
+    FileUtils.mkdir_p(TMP_DIR)
+  end
+
+  def teardown
+    FileUtils.rm_rf(TMP_DIR)
+  end
+
+  def build_project(num_pods)
+    path = File.join(TMP_DIR, "Pods.xcodeproj")
+    FileUtils.mkdir_p(path)
+    project = Pod::Project.new(path)
+    num_pods.times { |i| project.new_target(:static_library, "Pod#{i}", :ios) }
+    project.new_target(:static_library, POD_NAME, :ios)
+    project.save
+    project
+  end
+
+  def inject_spm(project)
+    manager = SPMManager.new
+    manager.dependency(
+      PodSpecStub.new(POD_NAME),
+      url: "https://github.com/software-mansion-labs/RaTeX.git",
+      requirement: { kind: "upToNextMajorVersion", minimumVersion: "0.1.0" },
+      products: ["RaTeX"]
+    )
+    manager.apply_on_post_install(InstallerStub.new(project))
+    project.save
+  end
+
+  # Simulates the state after an on-disk reload / incremental `pod install`:
+  # existing objects keep their counter-based UUIDs, but the generator counters
+  # reset to zero. This is what makes `Pod::Project#generate_uuid` hand back a
+  # UUID (`<prefix>00000000`) that already belongs to the root object.
+  def simulate_reload(project)
+    project.instance_variable_set(:@generated_uuids, [])
+    project.instance_variable_set(:@available_uuids, [])
+  end
+
+  def assert_loadable_project(path)
+    reopened = nil
+    assert_nothing_raised("Pods project must reload cleanly after SPM injection") do
+      reopened = Xcodeproj::Project.open(path)
+    end
+    root_uuid = reopened.root_object.uuid
+    assert(
+      reopened.objects_by_uuid[root_uuid].is_a?(Xcodeproj::Project::Object::PBXProject),
+      "rootObject UUID must resolve to a PBXProject"
+    )
+    package_uuids = reopened.root_object.package_references.map(&:uuid)
+    assert(
+      package_uuids.none? { |uuid| uuid == root_uuid },
+      "injected package reference must not collide with the root object UUID"
+    )
+    reopened
+  end
+
+  def test_spm_injection_on_freshly_generated_project_reloads_cleanly
+    project = build_project(88)
+    inject_spm(project)
+    assert_loadable_project(project.path)
+  end
+
+  def test_spm_injection_after_project_reload_does_not_collide_with_root_object
+    project = build_project(88)
+    simulate_reload(project)
+    inject_spm(project)
+    assert_loadable_project(project.path)
+  end
+
+  def test_injected_uuids_are_unique_across_all_objects
+    project = build_project(88)
+    simulate_reload(project)
+    inject_spm(project)
+    reopened = assert_loadable_project(project.path)
+    uuids = reopened.objects.map(&:uuid)
+    assert_equal(uuids.length, uuids.uniq.length, "all object UUIDs must be unique")
+  end
+end
diff --git a/packages/react-native/scripts/cocoapods/spm.rb b/packages/react-native/scripts/cocoapods/spm.rb
index 0995dfbfc972..baa2a04ee9d0 100644
--- a/packages/react-native/scripts/cocoapods/spm.rb
+++ b/packages/react-native/scripts/cocoapods/spm.rb
@@ -53,6 +53,29 @@ def apply_on_post_install(installer)
 
   private
 
+  # Creates a new object in the project with a UUID guaranteed not to collide
+  # with any UUID already present in the project.
+  #
+  # `Pod::Project` overrides `generate_available_uuid_list` with a fast,
+  # counter-based scheme (`<sha prefix><counter>0`) that deliberately skips
+  # collision checks, on the assumption that the whole Pods project is generated
+  # in a single pass. That assumption does not hold here: we run in a
+  # `post_install` hook, and the generator's counter can be out of sync with the
+  # UUIDs already assigned to existing objects (e.g. when the project has been
+  # reloaded from disk during an incremental install, the counter restarts at 0
+  # while the root object still occupies `<prefix>00000000`). Using `project.new`
+  # directly can therefore hand back a UUID that is already in use and overwrite
+  # an existing object (notably the root `PBXProject`), producing a Pods project
+  # Xcode refuses to load. We keep the deterministic scheme but probe forward
+  # until we find a UUID that is actually free.
+  def new_object(project, klass)
+    uuid = project.generate_uuid
+    uuid = project.generate_uuid while project.objects_by_uuid.key?(uuid)
+    object = klass.new(project, uuid)
+    object.initialize_defaults
+    object
+  end
+
   def log(msg)
     ::Pod::UI.puts "[SPM] #{msg}"
   end
@@ -76,7 +99,7 @@ def add_spm_to_target(project, target, url, requirement, products)
       pkg_class = Xcodeproj::Project::Object::XCLocalSwiftPackageReference
       pkg = project.root_object.package_references.find { |p| p.class == pkg_class && p.relative_path == url }
       if !pkg
-        pkg = project.new(pkg_class)
+        pkg = new_object(project, pkg_class)
         pkg.relative_path = url
         log(" Adding local package to workspace: #{pkg.inspect}")
         project.root_object.package_references << pkg
@@ -85,7 +108,7 @@ def add_spm_to_target(project, target, url, requirement, products)
       pkg_class = Xcodeproj::Project::Object::XCRemoteSwiftPackageReference
       pkg = project.root_object.package_references.find { |p| p.class == pkg_class && p.repositoryURL == url }
       if !pkg
-        pkg = project.new(pkg_class)
+        pkg = new_object(project, pkg_class)
         pkg.repositoryURL = url
         pkg.requirement = requirement
         log(" Adding remote package to workspace: #{pkg.inspect}")
@@ -101,7 +124,7 @@ def add_spm_to_target(project, target, url, requirement, products)
       next if ref
 
       log(" Adding product dependency #{product_name} to #{target.name}")
-      ref = project.new(ref_class)
+      ref = new_object(project, ref_class)
       ref.package = pkg
       ref.product_name = product_name
       target.package_product_dependencies << ref