diff --git a/clang/test/CodeGen/2007-06-18-SextAttrAggregate.c b/clang/test/CodeGen/2007-06-18-SextAttrAggregate.c
index daed3baf4643e..ccfdc1a1c6cfa 100644
--- a/clang/test/CodeGen/2007-06-18-SextAttrAggregate.c
+++ b/clang/test/CodeGen/2007-06-18-SextAttrAggregate.c
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -no-enable-noundef-analysis %s -o - -emit-llvm | FileCheck %s
-// XFAIL: target={{(aarch64|arm64).*}}, target=x86_64-pc-windows-msvc, target=x86_64-{{(pc|w64)}}-windows-gnu
+// XFAIL: target={{(aarch64|arm64).*}}, target=x86_64-pc-windows-msvc, target=x86_64-{{(pc|w64)}}-windows-gnu, target=x86_64-pc-windows-cygnus
 
 // PR1513
 
diff --git a/clang/test/CodeGen/debug-info-version.c b/clang/test/CodeGen/debug-info-version.c
index c7c2bb95017a2..485b80e2a5b10 100644
--- a/clang/test/CodeGen/debug-info-version.c
+++ b/clang/test/CodeGen/debug-info-version.c
@@ -1,4 +1,4 @@
-// REQUIRES: !system-windows
+// REQUIRES: !system-windows, !system-cygwin
 // RUN: %clang -g -S -emit-llvm -o - %s | FileCheck %s
 // RUN: %clang -S -emit-llvm -o - %s | FileCheck %s --check-prefix=NO_DEBUG
 int main (void) {
diff --git a/clang/test/CodeGenCXX/modules-vtable.cppm b/clang/test/CodeGenCXX/modules-vtable.cppm
index 6589b9f3c5d64..75f7598a63b06 100644
--- a/clang/test/CodeGenCXX/modules-vtable.cppm
+++ b/clang/test/CodeGenCXX/modules-vtable.cppm
@@ -1,4 +1,4 @@
-// REQUIRES: !system-windows
+// REQUIRES: !system-windows, !system-cygwin
 
 // RUN: rm -rf %t
 // RUN: split-file %s %t
diff --git a/clang/test/CodeGenCXX/pr70585.cppm b/clang/test/CodeGenCXX/pr70585.cppm
index ad4e13589d86e..d44a4f497285a 100644
--- a/clang/test/CodeGenCXX/pr70585.cppm
+++ b/clang/test/CodeGenCXX/pr70585.cppm
@@ -1,4 +1,4 @@
-// REQUIRES: !system-windows
+// REQUIRES: !system-windows, !system-cygwin
 
 // RUN: rm -rf %t
 // RUN: split-file %s %t
diff --git a/clang/test/Driver/cuda-detect-path.cu b/clang/test/Driver/cuda-detect-path.cu
index 8d249bd4c96d5..ce42ed75f7a8d 100644
--- a/clang/test/Driver/cuda-detect-path.cu
+++ b/clang/test/Driver/cuda-detect-path.cu
@@ -1,5 +1,5 @@
 // This tests uses the PATH environment variable.
-// REQUIRES: !system-windows
+// REQUIRES: !system-windows, !system-cygwin
 
 // RUN: env PATH=%S/Inputs/CUDA/usr/local/cuda/bin \
 // RUN:    %clang -v --target=i386-unknown-linux --sysroot=%S/no-cuda-there \
diff --git a/clang/test/Driver/hipspv-toolchain.hip b/clang/test/Driver/hipspv-toolchain.hip
index b2187acbcd5ab..3c175ebf433cc 100644
--- a/clang/test/Driver/hipspv-toolchain.hip
+++ b/clang/test/Driver/hipspv-toolchain.hip
@@ -1,4 +1,4 @@
-// UNSUPPORTED: system-windows
+// UNSUPPORTED: system-windows, system-cygwin
 
 // RUN: %clang -### -target x86_64-linux-gnu --offload=spirv64 \
 // RUN:   --no-offload-new-driver --hip-path=%S/Inputs/hipspv -nohipwrapperinc %s \
diff --git a/clang/test/Driver/ld-path.c b/clang/test/Driver/ld-path.c
index bc10b9e12e25a..e00b63d4eff5c 100644
--- a/clang/test/Driver/ld-path.c
+++ b/clang/test/Driver/ld-path.c
@@ -1,5 +1,5 @@
 /// This tests uses the PATH environment variable.
-// UNSUPPORTED: system-windows
+// UNSUPPORTED: system-windows, system-cygwin
 
 // RUN: cd %S
 
diff --git a/clang/test/Driver/program-path-priority.c b/clang/test/Driver/program-path-priority.c
index c940c4ced9442..b88c0f29f7f33 100644
--- a/clang/test/Driver/program-path-priority.c
+++ b/clang/test/Driver/program-path-priority.c
@@ -1,5 +1,5 @@
 /// Don't create symlinks on Windows
-// UNSUPPORTED: system-windows
+// UNSUPPORTED: system-windows, system-cygwin
 
 /// Check the priority used when searching for tools
 /// Names and locations are usually in this order:
diff --git a/clang/test/Driver/spirv-toolchain.cl b/clang/test/Driver/spirv-toolchain.cl
index 53e8455e3d3dd..54c794c77ea04 100644
--- a/clang/test/Driver/spirv-toolchain.cl
+++ b/clang/test/Driver/spirv-toolchain.cl
@@ -92,7 +92,7 @@
 // RUN: mkdir -p %t/versioned
 // RUN: touch %t/versioned/spirv-as-%llvm-version-major \
 // RUN:   && chmod +x %t/versioned/spirv-as-%llvm-version-major
-// RUN: %if !system-windows %{ env "PATH=%t/versioned" %clang -### --target=spirv64 -x cl -c --save-temps %s 2>&1 \
+// RUN: %if !system-windows && !system-cygwin %{ env "PATH=%t/versioned" %clang -### --target=spirv64 -x cl -c --save-temps %s 2>&1 \
 // RUN:   | FileCheck -DVERSION=%llvm-version-major --check-prefix=VERSIONED %s %}
 
 // VERSIONED: {{.*}}spirv-as-[[VERSION]]
diff --git a/clang/test/Interpreter/simple-exception.cpp b/clang/test/Interpreter/simple-exception.cpp
index 651e8d9402f89..8f7b515c142b0 100644
--- a/clang/test/Interpreter/simple-exception.cpp
+++ b/clang/test/Interpreter/simple-exception.cpp
@@ -1,7 +1,7 @@
 // clang-format off
 // UNSUPPORTED: system-aix
 // XFAIL for arm, or running on Windows.
-// XFAIL: target=arm-{{.*}}, target=armv{{.*}}, system-windows
+// XFAIL: target=arm-{{.*}}, target=armv{{.*}}, system-windows, system-cygwin
 // RUN: cat %s | clang-repl | FileCheck %s
 
 // Incompatible with msan. It passes with -O3 but fail -Oz. Interpreter
diff --git a/clang/test/Lexer/cross-windows-on-linux.cpp b/clang/test/Lexer/cross-windows-on-linux.cpp
index 3932ffcb33c82..ece16b1ac8550 100644
--- a/clang/test/Lexer/cross-windows-on-linux.cpp
+++ b/clang/test/Lexer/cross-windows-on-linux.cpp
@@ -10,4 +10,4 @@
 // on non-Windows unless -fms-extensions is passed. It won't fail in this way on
 // Windows because the filesystem will interpret the backslash as a directory
 // separator.
-// UNSUPPORTED: system-windows
+// UNSUPPORTED: system-windows, system-cygwin
diff --git a/clang/test/Modules/pr97313.cppm b/clang/test/Modules/pr97313.cppm
index 32c7112da091e..99795d6e43030 100644
--- a/clang/test/Modules/pr97313.cppm
+++ b/clang/test/Modules/pr97313.cppm
@@ -1,4 +1,4 @@
-// REQUIRES: !system-windows
+// REQUIRES: !system-windows, !system-cygwin
 //
 // RUN: rm -rf %t
 // RUN: mkdir -p %t
diff --git a/clang/test/Preprocessor/file_test.c b/clang/test/Preprocessor/file_test.c
index 945882ded7a6a..1e7e1dfe96dd9 100644
--- a/clang/test/Preprocessor/file_test.c
+++ b/clang/test/Preprocessor/file_test.c
@@ -1,4 +1,4 @@
-// UNSUPPORTED: system-windows
+// UNSUPPORTED: system-windows, system-cygwin
 // RUN: %clang -E -ffile-prefix-map=%p=/UNLIKELY_PATH/empty -c -o - %s | FileCheck %s
 // RUN: %clang -E -fmacro-prefix-map=%p=/UNLIKELY_PATH/empty -c -o - %s | FileCheck %s
 // RUN: %clang -E -fmacro-prefix-map=%p=/UNLIKELY_PATH=empty -c -o - %s | FileCheck %s -check-prefix CHECK-EVIL