diff --git a/cibuildwheel/platforms/android.py b/cibuildwheel/platforms/android.py
index 59c3869f..558e7001 100644
--- a/cibuildwheel/platforms/android.py
+++ b/cibuildwheel/platforms/android.py
@@ -140,6 +140,7 @@ def build(options: Options, tmp_path: Path) -> None:
             build_path.mkdir()
             python_dir = setup_target_python(config, build_path)
             build_env, android_env = setup_env(config, build_options, build_path, python_dir)
+
             state = BuildState(
                 config, build_options, build_path, python_dir, build_env, android_env
             )
@@ -228,6 +229,7 @@ def setup_env(
 
     # Apply custom environment variables, and check environment is still valid
     build_env = build_options.environment.as_dictionary(build_env)
+    build_env["CIBUILDWHEEL_BUILD_IDENTIFIER"] = config.identifier
     build_env["PIP_DISABLE_PIP_VERSION_CHECK"] = "1"
     for command in ["python"] if use_uv else ["python", "pip"]:
         command_path = call("which", command, env=build_env, capture_stdout=True).strip()
diff --git a/cibuildwheel/platforms/ios.py b/cibuildwheel/platforms/ios.py
index 223a833f..ac4caab3 100644
--- a/cibuildwheel/platforms/ios.py
+++ b/cibuildwheel/platforms/ios.py
@@ -482,6 +482,7 @@ def build(options: Options, tmp_path: Path) -> None:
                 build_frontend=build_frontend.name,
                 xbuild_tools=build_options.xbuild_tools,
             )
+            env["CIBUILDWHEEL_BUILD_IDENTIFIER"] = config.identifier
 
             compatible_wheel = find_compatible_wheel(built_wheels, config.identifier)
             if compatible_wheel:
diff --git a/cibuildwheel/platforms/linux.py b/cibuildwheel/platforms/linux.py
index 9b4559ba..310355d3 100644
--- a/cibuildwheel/platforms/linux.py
+++ b/cibuildwheel/platforms/linux.py
@@ -237,6 +237,7 @@ def build_in_container(
         env["PATH"] = f"{python_bin}:{env['PATH']}"
 
         env = build_options.environment.as_dictionary(env, executor=container.environment_executor)
+        env["CIBUILDWHEEL_BUILD_IDENTIFIER"] = config.identifier
 
         # check config python is still on PATH
         which_python = container.call(["which", "python"], env=env, capture_output=True).strip()
diff --git a/cibuildwheel/platforms/macos.py b/cibuildwheel/platforms/macos.py
index 3208bcd1..4fe002fc 100644
--- a/cibuildwheel/platforms/macos.py
+++ b/cibuildwheel/platforms/macos.py
@@ -466,6 +466,7 @@ def build(options: Options, tmp_path: Path) -> None:
                 build_options.environment,
                 build_frontend.name,
             )
+            env["CIBUILDWHEEL_BUILD_IDENTIFIER"] = config.identifier
             pip_version = None if use_uv else get_pip_version(env)
 
             compatible_wheel = find_compatible_wheel(built_wheels, config.identifier)
diff --git a/cibuildwheel/platforms/pyodide.py b/cibuildwheel/platforms/pyodide.py
index 53c66d9f..435dafa0 100644
--- a/cibuildwheel/platforms/pyodide.py
+++ b/cibuildwheel/platforms/pyodide.py
@@ -391,6 +391,7 @@ def build(options: Options, tmp_path: Path) -> None:
                 environment=build_options.environment,
                 user_pyodide_version=build_options.pyodide_version,
             )
+            env["CIBUILDWHEEL_BUILD_IDENTIFIER"] = config.identifier
             pip_version = get_pip_version(env)
             # The Pyodide command line runner mounts all directories in the host
             # filesystem into the Pyodide file system, except for the custom
diff --git a/cibuildwheel/platforms/windows.py b/cibuildwheel/platforms/windows.py
index 8b30c710..e05a58d6 100644
--- a/cibuildwheel/platforms/windows.py
+++ b/cibuildwheel/platforms/windows.py
@@ -466,6 +466,7 @@ def build(options: Options, tmp_path: Path) -> None:
                 build_options.environment,
                 build_frontend.name,
             )
+            env["CIBUILDWHEEL_BUILD_IDENTIFIER"] = config.identifier
             pip_version = None if use_uv else get_pip_version(env)
 
             compatible_wheel = find_compatible_wheel(built_wheels, config.identifier)
diff --git a/docs/options.md b/docs/options.md
index e6381009..6ace324b 100644
--- a/docs/options.md
+++ b/docs/options.md
@@ -669,6 +669,9 @@ Platform-specific environment variables are also available:<br/>
 !!! note
     cibuildwheel always defines the environment variable `CIBUILDWHEEL=1`. This can be useful for [building wheels with optional extensions](faq.md#optional-extensions).
 
+!!! note
+    For each per-build step (`before_build`, the build itself, `repair_command`, `before_test`, `test_command`), cibuildwheel also sets `CIBUILDWHEEL_BUILD_IDENTIFIER` to the current build identifier (e.g. `cp311-manylinux_x86_64`). This can be used in scripts to distinguish different builds.
+
 !!! note
     To do its work, cibuildwheel sets the variables `VIRTUALENV_PIP`, `DIST_EXTRA_CONFIG`, `SETUPTOOLS_EXT_SUFFIX`, `PIP_DISABLE_PIP_VERSION_CHECK`, `PIP_ROOT_USER_ACTION`, and it extends the variables `PATH` and `PIP_CONSTRAINT`. Your assignments to these options might be replaced or extended.