diff --git a/Makefile.inc1 b/Makefile.inc1
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -1082,6 +1082,9 @@
 	    -p ${WORLDTMP}/usr/include >/dev/null
 .if ${TARGET_ARCH} == "amd64"
 	mkdir -p ${WORLDTMP}/usr/include/i386
+.endif
+.if ${TARGET_ARCH} == "aarch64"
+	mkdir -p ${WORLDTMP}/usr/include/arm
 .endif
 	ln -sf ${.CURDIR}/sys ${WORLDTMP}
 .if ${MK_DEBUG_FILES} != "no"
@@ -1418,6 +1421,9 @@
 .if ${TARGET_ARCH} == "amd64"
 	-mkdir ${DESTDIR}/${DISTDIR}/${dist}/usr/include/i386
 .endif
+.if ${TARGET_ARCH} == "aarch64"
+	-mkdir ${DESTDIR}/${DISTDIR}/${dist}/usr/include/arm
+.endif
 .if ${MK_DEBUG_FILES} != "no"
 	${DESTDIR_MTREE} -f ${.CURDIR}/etc/mtree/BSD.debug.dist \
 	    -p ${DESTDIR}/${DISTDIR}/${dist}/usr/lib >/dev/null
@@ -1449,6 +1455,9 @@
 .if ${TARGET_ARCH} == "amd64"
 	echo "./${dist}/usr/include/i386 type=dir uname=root gname=wheel mode=0755" >> ${METALOG}
 .endif
+.if ${TARGET_ARCH} == "aarch64"
+	echo "./${dist}/usr/include/arm type=dir uname=root gname=wheel mode=0755" >> ${METALOG}
+.endif
 .for libcompat in ${libcompats}
 	${IMAKEENV} ${DISTR_MTREE} -C -f ${.CURDIR}/etc/mtree/BSD.lib${libcompat}.dist | \
 	    sed -e 's#^\./#./${dist}/usr/#' >> ${METALOG}
@@ -2902,6 +2911,9 @@
 	    -p ${NXBDESTDIR}/usr/include >/dev/null
 .if ${TARGET_ARCH} == "amd64"
 	mkdir -p ${NXBDESTDIR}/usr/include/i386
+.endif
+.if ${TARGET_ARCH} == "aarch64"
+	mkdir -p ${NXBDESTDIR}/usr/include/arm
 .endif
 	${_+_}cd ${.CURDIR}; ${NXBMAKE} \
 	    DESTDIR=${NXBDESTDIR} \
@@ -3591,6 +3603,9 @@
 .if ${TARGET_ARCH} == "amd64"
 	mkdir -p ${XDDESTDIR}/usr/include/i386
 .endif
+.if ${TARGET_ARCH} == "aarch64"
+	mkdir -p ${XDDESTDIR}/usr/include/arm
+.endif
 .for libcompat in ${libcompats}
 	${DESTDIR_MTREE} -f ${.CURDIR}/etc/mtree/BSD.lib${libcompat}.dist \
 	    -p ${XDDESTDIR}/usr >/dev/null
diff --git a/Makefile.libcompat b/Makefile.libcompat
--- a/Makefile.libcompat
+++ b/Makefile.libcompat
@@ -4,7 +4,7 @@
 __<${_this:T}>__:
 
 # Makefile for the compatibility libraries.
-# - 32-bit compat libraries on PowerPC, and AMD64.
+# - 32-bit compat libraries on PowerPC, AArch64, and AMD64.
 
 .if defined(_LIBCOMPATS)
 
diff --git a/lib/Makefile b/lib/Makefile
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -203,7 +203,8 @@
 SUBDIR.${MK_BHYVE}+=	libvmmapi
 .endif
 
-.if ${MACHINE_ARCH} != "powerpc"
+.if ${MACHINE_ARCH} != "powerpc" && \
+    (${TARGET_ARCH} != "aarch64" || !defined(COMPAT_32BIT))
 SUBDIR.${MK_OPENMP}+=	libomp
 .endif
 .if !defined(COMPAT_32BIT) && ${MK_USB} != "no"
diff --git a/share/mk/bsd.compat.mk b/share/mk/bsd.compat.mk
--- a/share/mk/bsd.compat.mk
+++ b/share/mk/bsd.compat.mk
@@ -63,6 +63,25 @@
 LIB32_MACHINE_ARCH=	powerpc
 LIB32WMAKEFLAGS=	\
 		LD="${XLD} -m elf32ppc_fbsd"
+
+.elif ${COMPAT_ARCH} == "aarch64"
+HAS_COMPAT=32
+.if empty(COMPAT_CPUTYPE)
+LIB32CPUFLAGS=	-march="armv7"
+.else
+LIB32CPUFLAGS=	-mcpu=${COMPAT_CPUTYPE}
+.endif
+
+LIB32CPUFLAGS+=	-m32
+.if ${COMPAT_COMPILER_TYPE} == "gcc"
+.else
+LIB32CPUFLAGS+=	-target armv7-unknown-freebsd${OS_REVISION}-gnueabihf
+.endif
+
+LIB32_MACHINE=	arm
+LIB32_MACHINE_ARCH=	armv7
+LIB32WMAKEFLAGS=	\
+		LD="${XLD} -m armelf_fbsd"
 .endif
 
 LIB32WMAKEFLAGS+= NM="${XNM}"
@@ -124,7 +143,9 @@
 LIB${_LIBCOMPAT}WMAKEENV+=	MACHINE_ARCH=${LIB${_LIBCOMPAT}_MACHINE_ARCH}
 
 # -B is needed to find /usr/lib32/crti.o for gcc.
-LIB${_LIBCOMPAT}CFLAGS+=	-B${WORLDTMP}/usr/lib${_libcompat}
+# -L should be implied by -B, but is needed for clang on arm64.
+LIB${_LIBCOMPAT}CFLAGS+=	-B${WORLDTMP}/usr/lib${_libcompat} \
+				-L${WORLDTMP}/usr/lib${_libcompat}
 .endfor
 
 .if defined(USE_COMPAT)
diff --git a/share/mk/src.opts.mk b/share/mk/src.opts.mk
--- a/share/mk/src.opts.mk
+++ b/share/mk/src.opts.mk
@@ -297,8 +297,8 @@
 .else
 __DEFAULT_NO_OPTIONS+=LLDB
 .endif
-# LIB32 is supported on amd64 and powerpc64
-.if (${__T} == "amd64" || ${__T} == "powerpc64")
+# LIB32 is supported on amd64, aarch64, and powerpc64
+.if (${__T} == "amd64" || ${__T} == "aarch64" || ${__T} == "powerpc64")
 __DEFAULT_YES_OPTIONS+=LIB32
 .else
 BROKEN_OPTIONS+=LIB32