diff --git a/library/std/src/sys/pal/unix/thread.rs b/library/std/src/sys/pal/unix/thread.rs
index 7e4a01a5ecd33..312d1c28803d9 100644
--- a/library/std/src/sys/pal/unix/thread.rs
+++ b/library/std/src/sys/pal/unix/thread.rs
@@ -847,11 +847,40 @@ pub mod guard {
             let stackptr = get_stack_start_aligned()?;
             let guardaddr = stackptr.addr();
             // Technically the number of guard pages is tunable and controlled
-            // by the security.bsd.stack_guard_page sysctl, but there are
-            // few reasons to change it from the default. The default value has
-            // been 1 ever since FreeBSD 11.1 and 10.4.
-            const GUARD_PAGES: usize = 1;
-            let guard = guardaddr..guardaddr + GUARD_PAGES * page_size;
+            // by the security.bsd.stack_guard_page sysctl.
+            // By default it is 1, checking once is enough since it is
+            // a boot time config value.
+            static LOCK: crate::sync::OnceLock<usize> = crate::sync::OnceLock::new();
+            let guard = guardaddr
+                ..guardaddr
+                    + *LOCK.get_or_init(|| {
+                        extern "C" {
+                            pub fn sysctlbyname(
+                                oid: *const libc::c_char,
+                                ov: *mut libc::c_void,
+                                osize: *mut libc::size_t,
+                                nv: *const libc::c_void,
+                                nsize: libc::size_t,
+                            ) -> libc::c_int;
+                        }
+                        let mut guard: usize = 0;
+                        let mut size = crate::mem::size_of_val(&guard);
+                        let oid = crate::ffi::CStr::from_bytes_with_nul(
+                            b"security.bsd.stack_guard_page\0",
+                        )
+                        .unwrap();
+                        let res = sysctlbyname(
+                            oid.as_ptr(),
+                            &mut guard as *mut _ as *mut _,
+                            &mut size as *mut _ as *mut _,
+                            crate::ptr::null_mut(),
+                            0,
+                        );
+                        if res == 0 {
+                            return guard;
+                        }
+                        1
+                    }) * page_size;
             Some(guard)
         } else if cfg!(target_os = "openbsd") {
             // OpenBSD stack already includes a guard page, and stack is