diff --git a/llvm/test/tools/llvm-objcopy/MachO/add-multiple-sections.test b/llvm/test/tools/llvm-objcopy/MachO/add-multiple-sections.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-objcopy/MachO/add-multiple-sections.test
@@ -0,0 +1,189 @@
+## This test verifies that llvm-objcopy can add multiple sections to a Mach-O binary.
+
+# RUN: yaml2obj %s -o %t
+# RUN: echo -n FOOabcdefg > %t.foo.data
+# RUN: echo -n BARabcdefg > %t.bar.data
+
+## Case 1: Add a new section twice into an existing segment.
+# RUN: llvm-objcopy --add-section __TEXT,__foo=%t.foo.data %t %t.foo.out
+# RUN: llvm-objcopy --add-section __TEXT,__bar=%t.bar.data %t.foo.out %t.foo.bar.out
+# RUN: llvm-readobj --sections --section-data %t.foo.bar.out \
+# RUN:   | FileCheck %s -check-prefix=CHECK-1
+
+## Case 2: Add two new sections into an existing segment.
+# RUN: llvm-objcopy --add-section __TEXT,__foo=%t.foo.data --add-section __TEXT,__bar=%t.bar.data %t %t.foo_bar.out
+# RUN: llvm-readobj --sections --section-data %t.foo_bar.out \
+# RUN:   | FileCheck %s -check-prefix=CHECK-1
+
+## Case 3: Add two new sections into two different segments.
+# RUN: llvm-objcopy --add-section __FOO,__foo=%t.foo.data --add-section __BAR,__bar=%t.bar.data %t %t.foo_bar.out
+# RUN: llvm-readobj --sections --section-data %t.foo_bar.out \
+# RUN:   | FileCheck %s -check-prefix=CHECK-2
+
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x01000007
+  cpusubtype:      0x00000003
+  filetype:        0x00000001
+  ncmds:           1
+  sizeofcmds:      152
+  flags:           0x00002000
+  reserved:        0x00000000
+LoadCommands:
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         152
+    segname:         __TEXT
+    vmaddr:          0
+    vmsize:          4
+    fileoff:         184
+    filesize:        4
+    maxprot:         7
+    initprot:        7
+    nsects:          1
+    flags:           0
+    Sections:
+      - sectname:        __text
+        segname:         __TEXT
+        addr:            0x0000000000000000
+        content:         'AABBCCDD'
+        size:            4
+        offset:          184
+        align:           0
+        reloff:          0x00000000
+        nreloc:          0
+        flags:           0x80000400
+        reserved1:       0x00000000
+        reserved2:       0x00000000
+        reserved3:       0x00000000
+
+# CHECK-1:        Sections [
+# CHECK-1-NEXT:    Section {
+# CHECK-1-NEXT:      Index: 0
+# CHECK-1-NEXT:      Name: __text (5F 5F 74 65 78 74 00 00 00 00 00 00 00 00 00 00)
+# CHECK-1-NEXT:      Segment: __TEXT (5F 5F 54 45 58 54 00 00 00 00 00 00 00 00 00 00)
+# CHECK-1-NEXT:      Address: 0x0
+# CHECK-1-NEXT:      Size: 0x4
+# CHECK-1-NEXT:      Offset: 344
+# CHECK-1-NEXT:      Alignment: 0
+# CHECK-1-NEXT:      RelocationOffset: 0x0
+# CHECK-1-NEXT:      RelocationCount: 0
+# CHECK-1-NEXT:      Type: Regular (0x0)
+# CHECK-1-NEXT:      Attributes [ (0x800004)
+# CHECK-1-NEXT:        PureInstructions (0x800000)
+# CHECK-1-NEXT:        SomeInstructions (0x4)
+# CHECK-1-NEXT:      ]
+# CHECK-1-NEXT:      Reserved1: 0x0
+# CHECK-1-NEXT:      Reserved2: 0x0
+# CHECK-1-NEXT:      Reserved3: 0x0
+# CHECK-1-NEXT:      SectionData (
+# CHECK-1-NEXT:        0000: AABBCCDD                             |....|
+# CHECK-1-NEXT:      )
+# CHECK-1-NEXT:    }
+# CHECK-1-NEXT:    Section {
+# CHECK-1-NEXT:      Index: 1
+# CHECK-1-NEXT:      Name: __foo (5F 5F 66 6F 6F 00 00 00 00 00 00 00 00 00 00 00)
+# CHECK-1-NEXT:      Segment: __TEXT (5F 5F 54 45 58 54 00 00 00 00 00 00 00 00 00 00)
+# CHECK-1-NEXT:      Address: 0x4
+# CHECK-1-NEXT:      Size: 0xA
+# CHECK-1-NEXT:      Offset: 348
+# CHECK-1-NEXT:      Alignment: 0
+# CHECK-1-NEXT:      RelocationOffset: 0x0
+# CHECK-1-NEXT:      RelocationCount: 0
+# CHECK-1-NEXT:      Type: Regular (0x0)
+# CHECK-1-NEXT:      Attributes [ (0x0)
+# CHECK-1-NEXT:      ]
+# CHECK-1-NEXT:      Reserved1: 0x0
+# CHECK-1-NEXT:      Reserved2: 0x0
+# CHECK-1-NEXT:      Reserved3: 0x0
+# CHECK-1-NEXT:      SectionData (
+# CHECK-1-NEXT:        0000: 464F4F61 62636465 6667               |FOOabcdefg|
+# CHECK-1-NEXT:      )
+# CHECK-1-NEXT:    }
+# CHECK-1-NEXT:    Section {
+# CHECK-1-NEXT:      Index: 2
+# CHECK-1-NEXT:      Name: __bar (5F 5F 62 61 72 00 00 00 00 00 00 00 00 00 00 00)
+# CHECK-1-NEXT:      Segment: __TEXT (5F 5F 54 45 58 54 00 00 00 00 00 00 00 00 00 00)
+# CHECK-1-NEXT:      Address: 0xE
+# CHECK-1-NEXT:      Size: 0xA
+# CHECK-1-NEXT:      Offset: 358
+# CHECK-1-NEXT:      Alignment: 0
+# CHECK-1-NEXT:      RelocationOffset: 0x0
+# CHECK-1-NEXT:      RelocationCount: 0
+# CHECK-1-NEXT:      Type: Regular (0x0)
+# CHECK-1-NEXT:      Attributes [ (0x0)
+# CHECK-1-NEXT:      ]
+# CHECK-1-NEXT:      Reserved1: 0x0
+# CHECK-1-NEXT:      Reserved2: 0x0
+# CHECK-1-NEXT:      Reserved3: 0x0
+# CHECK-1-NEXT:      SectionData (
+# CHECK-1-NEXT:        0000: 42415261 62636465 6667               |BARabcdefg|
+# CHECK-1-NEXT:      )
+# CHECK-1-NEXT:    }
+# CHECK-1-NEXT:  ]
+
+
+# CHECK-2:        Sections [
+# CHECK-2-NEXT:    Section {
+# CHECK-2-NEXT:      Index: 0
+# CHECK-2-NEXT:      Name: __text (5F 5F 74 65 78 74 00 00 00 00 00 00 00 00 00 00)
+# CHECK-2-NEXT:      Segment: __TEXT (5F 5F 54 45 58 54 00 00 00 00 00 00 00 00 00 00)
+# CHECK-2-NEXT:      Address: 0x0
+# CHECK-2-NEXT:      Size: 0x4
+# CHECK-2-NEXT:      Offset: 488
+# CHECK-2-NEXT:      Alignment: 0
+# CHECK-2-NEXT:      RelocationOffset: 0x0
+# CHECK-2-NEXT:      RelocationCount: 0
+# CHECK-2-NEXT:      Type: Regular (0x0)
+# CHECK-2-NEXT:      Attributes [ (0x800004)
+# CHECK-2-NEXT:        PureInstructions (0x800000)
+# CHECK-2-NEXT:        SomeInstructions (0x4)
+# CHECK-2-NEXT:      ]
+# CHECK-2-NEXT:      Reserved1: 0x0
+# CHECK-2-NEXT:      Reserved2: 0x0
+# CHECK-2-NEXT:      Reserved3: 0x0
+# CHECK-2-NEXT:      SectionData (
+# CHECK-2-NEXT:        0000: AABBCCDD                             |....|
+# CHECK-2-NEXT:      )
+# CHECK-2-NEXT:    }
+# CHECK-2-NEXT:    Section {
+# CHECK-2-NEXT:      Index: 1
+# CHECK-2-NEXT:      Name: __foo (5F 5F 66 6F 6F 00 00 00 00 00 00 00 00 00 00 00)
+# CHECK-2-NEXT:      Segment: __FOO (5F 5F 46 4F 4F 00 00 00 00 00 00 00 00 00 00 00)
+# CHECK-2-NEXT:      Address: 0xB8
+# CHECK-2-NEXT:      Size: 0xA
+# CHECK-2-NEXT:      Offset: 492
+# CHECK-2-NEXT:      Alignment: 0
+# CHECK-2-NEXT:      RelocationOffset: 0x0
+# CHECK-2-NEXT:      RelocationCount: 0
+# CHECK-2-NEXT:      Type: Regular (0x0)
+# CHECK-2-NEXT:      Attributes [ (0x0)
+# CHECK-2-NEXT:      ]
+# CHECK-2-NEXT:      Reserved1: 0x0
+# CHECK-2-NEXT:      Reserved2: 0x0
+# CHECK-2-NEXT:      Reserved3: 0x0
+# CHECK-2-NEXT:      SectionData (
+# CHECK-2-NEXT:        0000: 464F4F61 62636465 6667               |FOOabcdefg|
+# CHECK-2-NEXT:      )
+# CHECK-2-NEXT:    }
+# CHECK-2-NEXT:    Section {
+# CHECK-2-NEXT:      Index: 2
+# CHECK-2-NEXT:      Name: __bar (5F 5F 62 61 72 00 00 00 00 00 00 00 00 00 00 00)
+# CHECK-2-NEXT:      Segment: __BAR (5F 5F 42 41 52 00 00 00 00 00 00 00 00 00 00 00)
+# CHECK-2-NEXT:      Address: 0xB8
+# CHECK-2-NEXT:      Size: 0xA
+# CHECK-2-NEXT:      Offset: 502
+# CHECK-2-NEXT:      Alignment: 0
+# CHECK-2-NEXT:      RelocationOffset: 0x0
+# CHECK-2-NEXT:      RelocationCount: 0
+# CHECK-2-NEXT:      Type: Regular (0x0)
+# CHECK-2-NEXT:      Attributes [ (0x0)
+# CHECK-2-NEXT:      ]
+# CHECK-2-NEXT:      Reserved1: 0x0
+# CHECK-2-NEXT:      Reserved2: 0x0
+# CHECK-2-NEXT:      Reserved3: 0x0
+# CHECK-2-NEXT:      SectionData (
+# CHECK-2-NEXT:        0000: 42415261 62636465 6667               |BARabcdefg|
+# CHECK-2-NEXT:      )
+# CHECK-2-NEXT:    }
+# CHECK-2-NEXT:  ]
diff --git a/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp b/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp
--- a/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp
+++ b/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp
@@ -280,6 +280,7 @@
   StringRef TargetSegName = Pair.first;
   Section Sec(TargetSegName, Pair.second);
   Sec.Content = Obj.NewSectionsContents.save(Buf->getBuffer());
+  Sec.Size = Sec.Content.size();
 
   // Add the a section into an existing segment.
   for (LoadCommand &LC : Obj.LoadCommands) {