Index: lld/COFF/DriverUtils.cpp
===================================================================
--- lld/COFF/DriverUtils.cpp
+++ lld/COFF/DriverUtils.cpp
@@ -756,6 +756,28 @@
 
 COFFOptTable::COFFOptTable() : OptTable(InfoTable, true) {}
 
+// Set color diagnostics according to --color-diagnostics={auto,always,never}
+// or --no-color-diagnostics flags.
+static void handleColorDiagnostics(opt::InputArgList &Args) {
+  auto *Arg = Args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
+                              OPT_no_color_diagnostics);
+  if (!Arg)
+    return;
+  else if (Arg->getOption().getID() == OPT_color_diagnostics)
+    errorHandler().ColorDiagnostics = true;
+  else if (Arg->getOption().getID() == OPT_no_color_diagnostics)
+    errorHandler().ColorDiagnostics = false;
+  else {
+    StringRef S = Arg->getValue();
+    if (S == "always")
+      errorHandler().ColorDiagnostics = true;
+    else if (S == "never")
+      errorHandler().ColorDiagnostics = false;
+    else if (S != "auto")
+      error("unknown option: --color-diagnostics=" + S);
+  }
+}
+
 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &Args) {
   if (auto *Arg = Args.getLastArg(OPT_rsp_quoting)) {
     StringRef S = Arg->getValue();
@@ -799,6 +821,9 @@
 
   if (MissingCount)
     fatal(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
+
+  handleColorDiagnostics(Args);
+
   for (auto *Arg : Args.filtered(OPT_UNKNOWN))
     warn("ignoring unknown argument: " + Arg->getSpelling());
   return Args;
Index: lld/COFF/Options.td
===================================================================
--- lld/COFF/Options.td
+++ lld/COFF/Options.td
@@ -20,6 +20,10 @@
 def aligncomm : P<"aligncomm", "Set common symbol alignment">;
 def alternatename : P<"alternatename", "Define weak alias">;
 def base    : P<"base", "Base address of the program">;
+def color_diagnostics: Flag<["--"], "color-diagnostics">,
+  HelpText<"Use colors in diagnostics">;
+def color_diagnostics_eq: Joined<["--"], "color-diagnostics=">,
+  HelpText<"Use colors in diagnostics; one of 'always', 'never', 'auto'">;
 def defaultlib : P<"defaultlib", "Add the library to the list of input files">;
 def delayload : P<"delayload", "Delay loaded DLL name">;
 def entry   : P<"entry", "Name of entry point symbol">;
@@ -46,6 +50,8 @@
 def order   : P<"order", "Put functions in order">;
 def out     : P<"out", "Path to file to write output">;
 def natvis : P<"natvis", "Path to natvis file to embed in the PDB">;
+def no_color_diagnostics: F<"no-color-diagnostics">,
+  HelpText<"Do not use colors in diagnostics">;
 def pdb : P<"pdb", "PDB file path">;
 def pdbaltpath : P<"pdbaltpath", "PDB file path to embed in the image">;
 def section : P<"section", "Specify section attributes">;
Index: lld/ELF/DriverUtils.cpp
===================================================================
--- lld/ELF/DriverUtils.cpp
+++ lld/ELF/DriverUtils.cpp
@@ -70,7 +70,7 @@
     else if (S == "never")
       errorHandler().ColorDiagnostics = false;
     else if (S != "auto")
-      error("unknown option: -color-diagnostics=" + S);
+      error("unknown option: --color-diagnostics=" + S);
   }
 }
 
Index: lld/ELF/Options.td
===================================================================
--- lld/ELF/Options.td
+++ lld/ELF/Options.td
@@ -76,7 +76,7 @@
   HelpText<"Use colors in diagnostics">;
 
 def color_diagnostics_eq: J<"color-diagnostics=">,
-  HelpText<"Use colors in diagnostics">;
+  HelpText<"Use colors in diagnostics; one of 'always', 'never', 'auto'">;
 
 defm cref: B<"cref",
     "Output cross reference table",
Index: lld/test/COFF/color-diagnostics.test
===================================================================
--- /dev/null
+++ lld/test/COFF/color-diagnostics.test
@@ -0,0 +1,18 @@
+# Windows command prompt doesn't support ANSI escape sequences.
+# REQUIRES: shell
+
+# RUN: not lld-link -xyz --color-diagnostics /nosuchfile 2>&1 \
+# RUN:   | FileCheck -check-prefix=COLOR %s
+# RUN: not lld-link -xyz --color-diagnostics=always /nosuchfile 2>&1 \
+# RUN:   | FileCheck -check-prefix=COLOR %s
+
+# COLOR: {{lld-link: .\[0;1;35mwarning: .\[0mignoring unknown argument: -xyz}}
+# COLOR: {{lld-link: .\[0;1;31merror: .\[0mcould not open /nosuchfile}}
+
+# RUN: not lld-link /nosuchfile 2>&1 | FileCheck -check-prefix=NOCOLOR %s
+# RUN: not lld-link -color-diagnostics=never /nosuchfile 2>&1 \
+# RUN:   | FileCheck -check-prefix=NOCOLOR %s
+# RUN: not lld-link -color-diagnostics=always -no-color-diagnostics \
+# RUN:   /nosuchfile 2>&1 | FileCheck -check-prefix=NOCOLOR %s
+
+# NOCOLOR: lld-link: error: could not open /nosuchfile
Index: lld/wasm/Driver.cpp
===================================================================
--- lld/wasm/Driver.cpp
+++ lld/wasm/Driver.cpp
@@ -123,7 +123,7 @@
     if (S == "never")
       errorHandler().ColorDiagnostics = false;
     if (S != "auto")
-      error("unknown option: -color-diagnostics=" + S);
+      error("unknown option: --color-diagnostics=" + S);
   }
 }
 
Index: lld/wasm/Options.td
===================================================================
--- lld/wasm/Options.td
+++ lld/wasm/Options.td
@@ -21,7 +21,7 @@
   HelpText<"Use colors in diagnostics">;
 
 def color_diagnostics_eq: J<"color-diagnostics=">,
-  HelpText<"Use colors in diagnostics">;
+  HelpText<"Use colors in diagnostics; one of 'always', 'never', 'auto'">;
 
 defm demangle: B<"demangle",
     "Demangle symbol names",