diff --git a/llvm/test/tools/llvm-ar/thin-archive-relative-path.test b/llvm/test/tools/llvm-ar/thin-archive-relative-path.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-ar/thin-archive-relative-path.test
@@ -0,0 +1,19 @@
+RUN: rm -rf %t && mkdir -p %t/foo %t/bar 
+
+RUN: yaml2obj %S/Inputs/elf.yaml -o %t/foo/elf.o
+RUN: cp %t/foo/elf.o %t/bar/elf.o
+RUN: cd %t
+
+Test a case in which CWD does not contain the archive, ensure replacement behaves as expected
+
+RUN: llvm-ar cr --thin foo/lib.a foo/elf.o
+RUN: llvm-ar t foo/lib.a  | FileCheck %s --check-prefix=FOO --implicit-check-not {{.}}
+
+RUN: llvm-ar cr --thin foo/lib.a bar/elf.o
+RUN: llvm-ar t foo/lib.a  | FileCheck %s --check-prefixes=FOO,BAR --implicit-check-not {{.}}
+
+RUN: llvm-ar cr --thin foo/lib.a foo/elf.o
+RUN: llvm-ar t foo/lib.a  | FileCheck %s --check-prefixes=FOO,BAR --implicit-check-not {{.}}
+
+FOO: foo/elf.o
+BAR: foo/../bar/elf.o
diff --git a/llvm/tools/llvm-ar/llvm-ar.cpp b/llvm/tools/llvm-ar/llvm-ar.cpp
--- a/llvm/tools/llvm-ar/llvm-ar.cpp
+++ b/llvm/tools/llvm-ar/llvm-ar.cpp
@@ -875,8 +875,16 @@
 
   if (Operation == QuickAppend || Members.empty())
     return IA_AddOldMember;
-  auto MI = find_if(
-      Members, [Name](StringRef Path) { return comparePaths(Name, Path); });
+
+  auto MI = find_if(Members, [Name](StringRef Path) {
+    if (Thin && !sys::path::is_absolute(Path)) {
+      Expected<std::string> PathOrErr =
+          computeArchiveRelativePath(ArchiveName, Path);
+      return comparePaths(Name, PathOrErr ? *PathOrErr : Path);
+    } else {
+      return comparePaths(Name, Path);
+    }
+  });
 
   if (MI == Members.end())
     return IA_AddOldMember;