diff --git a/libc-test/semver/netbsd.txt b/libc-test/semver/netbsd.txt
index 3dc84da635963..b8fd4a194cd36 100644
--- a/libc-test/semver/netbsd.txt
+++ b/libc-test/semver/netbsd.txt
@@ -628,6 +628,7 @@ MADV_NORMAL
 MADV_RANDOM
 MADV_SEQUENTIAL
 MADV_WILLNEED
+MAP_ALIGNED
 MAP_ALIGNMENT_16MB
 MAP_ALIGNMENT_1TB
 MAP_ALIGNMENT_256TB
diff --git a/src/unix/bsd/netbsdlike/netbsd/mod.rs b/src/unix/bsd/netbsdlike/netbsd/mod.rs
index fd7175583e9a9..b100b3e14259a 100644
--- a/src/unix/bsd/netbsdlike/netbsd/mod.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/mod.rs
@@ -2384,6 +2384,19 @@ pub const GRND_NONBLOCK: ::c_uint = 0x1;
 pub const GRND_RANDOM: ::c_uint = 0x2;
 pub const GRND_INSECURE: ::c_uint = 0x4;
 
+cfg_if! {
+
+    if #[cfg(libc_const_extern_fn)] {
+        pub const fn MAP_ALIGNED(alignment: ::c_int) -> ::c_int {
+            alignment << MAP_ALIGNMENT_SHIFT
+        }
+    } else {
+        pub fn MAP_ALIGNED(alignment: ::c_int) -> ::c_int {
+            alignment << MAP_ALIGNMENT_SHIFT
+        }
+    }
+}
+
 const_fn! {
     {const} fn _ALIGN(p: usize) -> usize {
         (p + _ALIGNBYTES) & !_ALIGNBYTES