diff --git a/source/isaaclab/changelog.d/fix-openblas-fork-crash.rst b/source/isaaclab/changelog.d/fix-openblas-fork-crash.rst
new file mode 100644
index 00000000000..e7a4233ea9c
--- /dev/null
+++ b/source/isaaclab/changelog.d/fix-openblas-fork-crash.rst
@@ -0,0 +1,15 @@
+Fixed
+^^^^^
+
+* Fixed a ``SIGSEGV`` crash during Kit startup caused by NumPy's bundled
+  OpenBLAS ``pthread_atfork`` handler.  When ``import torch`` (or any
+  transitive NumPy import) runs before :class:`AppLauncher` creates the
+  :class:`~isaacsim.SimulationApp`, OpenBLAS spawns worker threads and
+  registers ``blas_thread_shutdown_`` as a child-side ``atfork`` handler.
+  Kit's ``libomni.platforminfo.plugin`` then calls ``fork()`` during
+  startup; in the child process the handler tries to ``pthread_join``
+  threads that no longer exist, causing a segmentation fault.  The fix
+  sets ``OPENBLAS_NUM_THREADS=1`` (via ``setdefault``) before the library
+  is loaded so that no worker threads are created and the handler is a
+  safe no-op.  Both :mod:`app_launcher` (for standalone scripts) and
+  ``tools/conftest.py`` (for CI test subprocesses) are patched.
diff --git a/source/isaaclab/isaaclab/app/app_launcher.py b/source/isaaclab/isaaclab/app/app_launcher.py
index 2bdb8a08932..e036d46172f 100644
--- a/source/isaaclab/isaaclab/app/app_launcher.py
+++ b/source/isaaclab/isaaclab/app/app_launcher.py
@@ -24,6 +24,16 @@
 import sys
 from typing import Any, Literal
 
+# Prevent OpenBLAS fork-safety crash.  NumPy/SciPy ship a bundled OpenBLAS
+# that spawns worker threads and registers a pthread_atfork child handler
+# (blas_thread_shutdown_).  When Kit's platform-info plugin calls fork()
+# during startup the handler runs in the child and tries to pthread_join
+# threads that were not carried across the fork → SIGSEGV.  Setting the
+# thread count to 1 *before* the library is loaded avoids the crash because
+# no worker threads are created and the atfork handler becomes a no-op.
+# Uses setdefault so that an explicit user/CI setting is respected.
+os.environ.setdefault("OPENBLAS_NUM_THREADS", "1")
+
 with contextlib.suppress(ModuleNotFoundError):
     import isaacsim  # noqa: F401
     from isaacsim import SimulationApp
diff --git a/tools/conftest.py b/tools/conftest.py
index 15aaa232364..514cde4cacf 100644
--- a/tools/conftest.py
+++ b/tools/conftest.py
@@ -316,6 +316,14 @@ def run_individual_tests(test_files, workspace_root, isaacsim_ci):
         file_name = os.path.basename(test_file)
         env = os.environ.copy()
         env["PYTHONFAULTHANDLER"] = "1"
+        # Prevent OpenBLAS fork-safety crash: when NumPy or SciPy is imported
+        # before Kit starts, OpenBLAS spawns a worker-thread pool and registers
+        # a pthread_atfork handler (blas_thread_shutdown_).  Kit's platform-info
+        # plugin calls fork() during startup; in the child the handler tries to
+        # pthread_join threads that no longer exist → SIGSEGV.  Limiting
+        # OpenBLAS to a single thread before the subprocess starts avoids the
+        # crash because no worker threads are created and the handler is a no-op.
+        env.setdefault("OPENBLAS_NUM_THREADS", "1")
 
         timeout = test_settings.PER_TEST_TIMEOUTS.get(file_name, test_settings.DEFAULT_TIMEOUT)