diff --git a/lld/ELF/Arch/AArch64.cpp b/lld/ELF/Arch/AArch64.cpp
--- a/lld/ELF/Arch/AArch64.cpp
+++ b/lld/ELF/Arch/AArch64.cpp
@@ -195,7 +195,7 @@
 }
 
 void AArch64::writeGotPlt(uint8_t *buf, const Symbol &) const {
-  write64le(buf, in.plt->getVA());
+  write64(buf, in.plt->getVA());
 }
 
 void AArch64::writePltHeader(uint8_t *buf) const {
@@ -323,12 +323,12 @@
   case R_AARCH64_ABS16:
   case R_AARCH64_PREL16:
     checkIntUInt(loc, val, 16, rel);
-    write16le(loc, val);
+    write16(loc, val);
     break;
   case R_AARCH64_ABS32:
   case R_AARCH64_PREL32:
     checkIntUInt(loc, val, 32, rel);
-    write32le(loc, val);
+    write32(loc, val);
     break;
   case R_AARCH64_PLT32:
     checkInt(loc, val, 32, rel);
@@ -336,7 +336,7 @@
     break;
   case R_AARCH64_ABS64:
   case R_AARCH64_PREL64:
-    write64le(loc, val);
+    write64(loc, val);
     break;
   case R_AARCH64_ADD_ABS_LO12_NC:
     or32AArch64Imm(loc, val);
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -146,6 +146,7 @@
       StringSwitch<std::pair<ELFKind, uint16_t>>(s)
           .Cases("aarch64elf", "aarch64linux", "aarch64_elf64_le_vec",
                  {ELF64LEKind, EM_AARCH64})
+          .Cases("aarch64elfb", "aarch64linuxb", {ELF64BEKind, EM_AARCH64})
           .Cases("armelf", "armelf_linux_eabi", {ELF32LEKind, EM_ARM})
           .Case("elf32_x86_64", {ELF32LEKind, EM_X86_64})
           .Cases("elf32btsmip", "elf32btsmipn32", {ELF32BEKind, EM_MIPS})
diff --git a/lld/ELF/ScriptParser.cpp b/lld/ELF/ScriptParser.cpp
--- a/lld/ELF/ScriptParser.cpp
+++ b/lld/ELF/ScriptParser.cpp
@@ -412,6 +412,7 @@
       .Case("elf32-x86-64", {ELF32LEKind, EM_X86_64})
       .Case("elf64-aarch64", {ELF64LEKind, EM_AARCH64})
       .Case("elf64-littleaarch64", {ELF64LEKind, EM_AARCH64})
+      .Case("elf64-bigaarch64", {ELF64BEKind, EM_AARCH64})
       .Case("elf32-powerpc", {ELF32BEKind, EM_PPC})
       .Case("elf32-powerpcle", {ELF32LEKind, EM_PPC})
       .Case("elf64-powerpc", {ELF64BEKind, EM_PPC64})
diff --git a/lld/test/ELF/aarch64-abs16.s b/lld/test/ELF/aarch64-abs16.s
--- a/lld/test/ELF/aarch64-abs16.s
+++ b/lld/test/ELF/aarch64-abs16.s
@@ -3,6 +3,8 @@
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs255.s -o %t255.o
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs256.s -o %t256.o
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs257.s -o %t257.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64_be %s -o %t.be.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64_be %S/Inputs/abs256.s -o %t256.be.o
 
 .globl _start
 _start:
@@ -12,6 +14,8 @@
 
 // RUN: ld.lld %t.o %t256.o -o %t
 // RUN: llvm-objdump -s --section=.data %t | FileCheck %s --check-prefixes=CHECK,LE
+// RUN: ld.lld %t.be.o %t256.be.o -o %t.be
+// RUN: llvm-objdump -s --section=.data %t.be | FileCheck %s --check-prefixes=CHECK,BE
 
 // CHECK: Contents of section .data:
 // 220158: S = 0x100, A = 0xfeff
@@ -19,6 +23,7 @@
 // 22015c: S = 0x100, A = -0x8100
 //         S + A = 0x8000
 // LE-NEXT: 220158 ffff0080
+// BE-NEXT: 220158 ffff8000
 
 // RUN: not ld.lld %t.o %t255.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=OVERFLOW1
 // OVERFLOW1: relocation R_AARCH64_ABS16 out of range: -32769 is not in [-32768, 65535]; references foo
diff --git a/lld/test/ELF/aarch64-abs32.s b/lld/test/ELF/aarch64-abs32.s
--- a/lld/test/ELF/aarch64-abs32.s
+++ b/lld/test/ELF/aarch64-abs32.s
@@ -3,6 +3,8 @@
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs255.s -o %t255.o
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs256.s -o %t256.o
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs257.s -o %t257.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64_be %s -o %t.be.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64_be %S/Inputs/abs256.s -o %t256.be.o
 
 .globl _start
 _start:
@@ -12,6 +14,8 @@
 
 // RUN: ld.lld %t.o %t256.o -o %t
 // RUN: llvm-objdump -s --section=.data %t | FileCheck %s --check-prefixes=CHECK,LE
+// RUN: ld.lld %t.be.o %t256.be.o -o %t.be
+// RUN: llvm-objdump -s --section=.data %t.be | FileCheck %s --check-prefixes=CHECK,BE
 
 // CHECK: Contents of section .data:
 // 220158: S = 0x100, A = 0xfffffeff
@@ -19,6 +23,7 @@
 // 22015c: S = 0x100, A = -0x80000100
 //         S + A = 0x80000000
 // LE-NEXT: 220158 ffffffff 00000080
+// BE-NEXT: 220158 ffffffff 80000000
 
 // RUN: not ld.lld %t.o %t255.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=OVERFLOW1
 // OVERFLOW1: relocation R_AARCH64_ABS32 out of range: -2147483649 is not in [-2147483648, 4294967295]; references foo
diff --git a/lld/test/ELF/aarch64-data-relocs.s b/lld/test/ELF/aarch64-data-relocs.s
--- a/lld/test/ELF/aarch64-data-relocs.s
+++ b/lld/test/ELF/aarch64-data-relocs.s
@@ -4,6 +4,11 @@
 // RUN: ld.lld %t.o %t256.o -o %t
 // RUN: llvm-objdump -s %t | FileCheck %s --check-prefixes=CHECK,LE
 
+// RUN: llvm-mc -filetype=obj -triple=aarch64_be %s -o %t.be.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64_be %S/Inputs/abs256.s -o %t256.be.o
+// RUN: ld.lld %t.be.o %t256.be.o -o %t.be
+// RUN: llvm-objdump -s %t.be | FileCheck %s --check-prefixes=CHECK,BE
+
 .globl _start
 _start:
 .section .R_AARCH64_ABS64, "ax",@progbits
@@ -13,6 +18,7 @@
 // S + A = 0x124
 // CHECK: Contents of section .R_AARCH64_ABS64:
 // LE-NEXT: 210120 24010000 00000000
+// BE-NEXT: 210120 00000000 00000124
 
 .section .R_AARCH64_PREL64, "ax",@progbits
   .xword foo - . + 0x24
@@ -20,3 +26,4 @@
 // S + A - P = 0x100 + 0x24 - 0x210128 = 0xffffffffffdefffc
 // CHECK: Contents of section .R_AARCH64_PREL64:
 // LE-NEXT: 210128 fcffdeff ffffffff
+// BE-NEXT: 210128 ffffffff ffdefffc
diff --git a/lld/test/ELF/aarch64-prel16.s b/lld/test/ELF/aarch64-prel16.s
--- a/lld/test/ELF/aarch64-prel16.s
+++ b/lld/test/ELF/aarch64-prel16.s
@@ -3,6 +3,8 @@
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs255.s -o %t255.o
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs256.s -o %t256.o
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs257.s -o %t257.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64_be %s -o %t.be.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64_be %S/Inputs/abs256.s -o %t256.be.o
 
 .globl _start
 _start:
@@ -16,6 +18,8 @@
 //       if it is already fixed. Then, update addends accordingly.
 // RUN: ld.lld -z max-page-size=4096 %t.o %t256.o -o %t
 // RUN: llvm-objdump -s --section=.data %t | FileCheck %s --check-prefixes=CHECK,LE
+// RUN: ld.lld -z max-page-size=4096 %t.be.o %t256.be.o -o %t.be
+// RUN: llvm-objdump -s --section=.data %t.be | FileCheck %s --check-prefixes=CHECK,BE
 
 // CHECK: Contents of section .data:
 // 202158: S = 0x100, A = 0x212157, P = 0x202158
diff --git a/lld/test/ELF/aarch64-prel32.s b/lld/test/ELF/aarch64-prel32.s
--- a/lld/test/ELF/aarch64-prel32.s
+++ b/lld/test/ELF/aarch64-prel32.s
@@ -3,6 +3,8 @@
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs255.s -o %t255.o
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs256.s -o %t256.o
 // RUN: llvm-mc -filetype=obj -triple=aarch64 %S/Inputs/abs257.s -o %t257.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64_be %s -o %t.be.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64_be %S/Inputs/abs256.s -o %t256.be.o
 
 .globl _start
 _start:
@@ -16,6 +18,8 @@
 //       if it is already fixed. Then, update addends accordingly.
 // RUN: ld.lld -z max-page-size=4096 %t.o %t256.o -o %t
 // RUN: llvm-objdump -s --section=.data %t | FileCheck %s --check-prefixes=CHECK,LE
+// RUN: ld.lld -z max-page-size=4096 %t.be.o %t256.be.o -o %t.be
+// RUN: llvm-objdump -s --section=.data %t.be | FileCheck %s --check-prefixes=CHECK,BE
 
 // CHECK: Contents of section .data:
 // 202158: S = 0x100, A = 0x100202057, P = 0x202158
@@ -23,6 +27,7 @@
 // 20215c: S = 0x100, A = -0x7fdfdfa4, P = 0x20215c
 //         S + A - P = 0x80000000
 // LE-NEXT: 202158 ffffffff 00000080
+// BE-NEXT: 202158 ffffffff 80000000
 
 // RUN: not ld.lld -z max-page-size=4096 %t.o %t255.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=OVERFLOW1
 // OVERFLOW1: relocation R_AARCH64_PREL32 out of range: -2147483649 is not in [-2147483648, 4294967295]; references foo
diff --git a/lld/test/ELF/emulation-aarch64.s b/lld/test/ELF/emulation-aarch64.s
--- a/lld/test/ELF/emulation-aarch64.s
+++ b/lld/test/ELF/emulation-aarch64.s
@@ -12,11 +12,23 @@
 # RUN: ld.lld -m aarch64_elf64_le_vec %t.o -o %taosp
 # RUN: llvm-readobj --file-headers %taosp | FileCheck --check-prefixes=AARCH64,LE %s
 
+# RUN: llvm-mc -filetype=obj -triple=aarch64_be %s -o %t.be.o
+# RUN: ld.lld %t.be.o -o %t
+# RUN: llvm-readobj --file-headers %t | FileCheck --check-prefixes=AARCH64,BE %s
+# RUN: ld.lld -m aarch64linuxb %t.be.o -o %t1.be
+# RUN: llvm-readobj --file-headers %t1.be | FileCheck --check-prefixes=AARCH64,BE %s
+# RUN: ld.lld -m aarch64elfb %t.be.o -o %t2.be
+# RUN: llvm-readobj --file-headers %t2.be | FileCheck --check-prefixes=AARCH64,BE %s
+# RUN: echo 'OUTPUT_FORMAT(elf64-bigaarch64)' > %t.script
+# RUN: ld.lld %t.script %t.be.o -o %t3.be
+# RUN: llvm-readobj --file-headers %t3.be | FileCheck --check-prefixes=AARCH64,BE %s
+
 # AARCH64:      ElfHeader {
 # AARCH64-NEXT:   Ident {
 # AARCH64-NEXT:     Magic: (7F 45 4C 46)
 # AARCH64-NEXT:     Class: 64-bit (0x2)
 # LE-NEXT:          DataEncoding: LittleEndian (0x1)
+# BE-NEXT:          DataEncoding: BigEndian (0x2)
 # AARCH64-NEXT:     FileVersion: 1
 # AARCH64-NEXT:     OS/ABI: SystemV (0x0)
 # AARCH64-NEXT:     ABIVersion: 0