diff --git a/conan/tools/env/environment.py b/conan/tools/env/environment.py
index 10936bfc2ae..aac022c1f5b 100644
--- a/conan/tools/env/environment.py
+++ b/conan/tools/env/environment.py
@@ -169,6 +169,9 @@ def deploy_base_folder(self, package_folder, deploy_folder):
             if v is _EnvVarPlaceHolder:
                 continue
             rel_path = os.path.relpath(v, package_folder)
+            if rel_path.startswith(".."):
+                # If it is pointing to a folder outside of the package, then do not relocate
+                continue
             self._values[i] = os.path.join(deploy_folder, rel_path)
 
     def set_relative_base_folder(self, folder):
diff --git a/conans/model/build_info.py b/conans/model/build_info.py
index 9f7dd2d10eb..ca058c798de 100644
--- a/conans/model/build_info.py
+++ b/conans/model/build_info.py
@@ -390,6 +390,9 @@ def set_relative_base_folder(self, folder):
     def deploy_base_folder(self, package_folder, deploy_folder):
         def relocate(el):
             rel_path = os.path.relpath(el, package_folder)
+            if rel_path.startswith(".."):
+                # If it is pointing to a folder outside of the package, then do not relocate
+                return el
             return os.path.join(deploy_folder, rel_path)
 
         for varname in _DIRS_VAR_NAMES:
diff --git a/conans/test/functional/command/test_install_deploy.py b/conans/test/functional/command/test_install_deploy.py
index e45d70ad1b6..f9fd31d42af 100644
--- a/conans/test/functional/command/test_install_deploy.py
+++ b/conans/test/functional/command/test_install_deploy.py
@@ -405,3 +405,33 @@ def deploy(graph, output_folder, **kwargs):
     tc.run(f"install . --deployer=my_deploy -of='{tmp_folder}' --deployer-folder='{deployer_output}'")
     assert f"Deployer output: {deployer_output}" in tc.out
     assert f"Deployer output: {tmp_folder}" not in tc.out
+
+
+def test_not_deploy_absolute_paths():
+    """ Absolute paths, for system packages, don't need to be relativized
+    https://github.com/conan-io/conan/issues/15242
+    """
+    c = TestClient()
+    some_abs_path = temp_folder().replace("\\", "/")
+    conanfile = textwrap.dedent(f"""
+        from conan import ConanFile
+        class Pkg(ConanFile):
+            name = "pkg"
+            version = "1.0"
+            def package_info(self):
+                self.cpp_info.includedirs = ["{some_abs_path}/myusr/include"]
+                self.cpp_info.libdirs = ["{some_abs_path}/myusr/lib"]
+                self.buildenv_info.define_path("MYPATH", "{some_abs_path}/mypath")
+        """)
+    c.save({"conanfile.py": conanfile})
+    c.run("create .")
+
+    # if we deploy one --requires, we get that package
+    c.run("install  --requires=pkg/1.0 --deployer=full_deploy -g CMakeDeps -g CMakeToolchain "
+          "-s os=Linux -s:b os=Linux -s arch=x86_64 -s:b arch=x86_64")
+    data = c.load("pkg-release-x86_64-data.cmake")
+    assert f'set(pkg_INCLUDE_DIRS_RELEASE "{some_abs_path}/myusr/include")' in data
+    assert f'set(pkg_LIB_DIRS_RELEASE "{some_abs_path}/myusr/lib")' in data
+
+    env = c.load("conanbuildenv-release-x86_64.sh")
+    assert f'export MYPATH="{some_abs_path}/mypath"' in env