diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -3014,7 +3014,25 @@
     return false;
   };
 
-  if (parseMany(parseOp))
+  auto parseManyWithOptionalComma = [&]() -> bool {
+    if (parseOptionalToken(AsmToken::EndOfStatement))
+      return false;
+    while (true) {
+      if (parseOp())
+        return true;
+      if (parseOptionalToken(AsmToken::EndOfStatement))
+        return false;
+      if (parseOptionalToken(AsmToken::Comma) &&
+          check(getTok().isNot(AsmToken::String), "expected string"))
+        return true;
+    }
+    return false;
+  };
+
+  // Support space as separtors for .ascii directive. See the discussion in
+  // https://reviews.llvm.org/D91460 for more details
+  if ((!ZeroTerminated && parseManyWithOptionalComma()) ||
+      (ZeroTerminated && parseMany(parseOp)))
     return addErrorSuffix(" in '" + Twine(IDVal) + "' directive");
   return false;
 }
diff --git a/llvm/test/MC/AsmParser/AArch64/directive-parse-err.s b/llvm/test/MC/AsmParser/AArch64/directive-parse-err.s
--- a/llvm/test/MC/AsmParser/AArch64/directive-parse-err.s
+++ b/llvm/test/MC/AsmParser/AArch64/directive-parse-err.s
@@ -13,7 +13,7 @@
 	.set   ident3, 0 $
 	// CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
 	.set   ident3, 0 // EOL COMMENT
-	// CHECK: [[@LINE+1]]:20: error: unexpected token in '.ascii' directive
+	// CHECK: [[@LINE+1]]:20: error: expected string in '.ascii' directive
 	.ascii  "string1" $
 	// CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
 	.ascii  "string1" // EOL COMMENT
diff --git a/llvm/test/MC/AsmParser/directive_ascii.s b/llvm/test/MC/AsmParser/directive_ascii.s
--- a/llvm/test/MC/AsmParser/directive_ascii.s
+++ b/llvm/test/MC/AsmParser/directive_ascii.s
@@ -48,3 +48,10 @@
 TEST7:
         .ascii "\x64\Xa6B"
         .ascii "\xface\x0Fe"
+
+# CHECK: TEST8:
+# CHECK: .byte 65
+# CHECK: .byte 66
+# CHECK: .byte 67
+TEST8:
+        .ascii "A", "B" "C"