diff --git a/mak/COPY b/mak/COPY
index ce675bf454e..de13c4aecd3 100644
--- a/mak/COPY
+++ b/mak/COPY
@@ -257,6 +257,7 @@ COPY=\
 	\
 	$(IMPDIR)\core\sys\openbsd\dlfcn.d \
 	$(IMPDIR)\core\sys\openbsd\err.d \
+	$(IMPDIR)\core\sys\openbsd\pthread_np.d \
 	$(IMPDIR)\core\sys\openbsd\stdlib.d \
 	$(IMPDIR)\core\sys\openbsd\string.d \
 	$(IMPDIR)\core\sys\openbsd\time.d \
diff --git a/mak/SRCS b/mak/SRCS
index 955119dcd61..e3d1d20c6d9 100644
--- a/mak/SRCS
+++ b/mak/SRCS
@@ -257,6 +257,7 @@ SRCS=\
 	\
 	src\core\sys\openbsd\dlfcn.d \
 	src\core\sys\openbsd\err.d \
+	src\core\sys\openbsd\pthread_np.d \
 	src\core\sys\openbsd\stdlib.d \
 	src\core\sys\openbsd\string.d \
 	src\core\sys\openbsd\time.d \
diff --git a/src/core/sys/openbsd/pthread_np.d b/src/core/sys/openbsd/pthread_np.d
new file mode 100644
index 00000000000..98d17fc92b5
--- /dev/null
+++ b/src/core/sys/openbsd/pthread_np.d
@@ -0,0 +1,23 @@
+/**
+  * D header file for OpenBSD pthread_np.h.
+  *
+  * Copyright: Copyright © 2021, The D Language Foundation
+  * License: <a href="http://www.boost.org/LICENSE_1_0.txt">Boost License 1.0</a>.
+  * Authors: Brian Callahan
+  */
+module core.sys.openbsd.pthread_np;
+
+version (OpenBSD):
+extern (C):
+nothrow:
+@nogc:
+
+public import core.sys.posix.sys.types;
+private import core.sys.posix.signal : stack_t;
+
+int pthread_mutexattr_getkind_np(pthread_mutexattr_t);
+int pthread_mutexattr_setkind_np(pthread_mutexattr_t*, int);
+void pthread_get_name_np(pthread_t, char*, size_t);
+void pthread_set_name_np(pthread_t, const(char)*);
+int pthread_stackseg_np(pthread_t, stack_t*);
+int pthread_main_np();