diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index 6810b59..eba2be1 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -19,6 +19,7 @@ jobs:
         os:
           - ubuntu
           - macos
+          - windows
         
         ruby:
           - "3.2"
@@ -47,4 +48,4 @@ jobs:
     
     - name: Run tests
       timeout-minutes: 10
-      run: bundle exec bake test
+      run: bundle exec sus --verbose
diff --git a/lib/io/stream/buffered.rb b/lib/io/stream/buffered.rb
index a1660fa..ecdc342 100644
--- a/lib/io/stream/buffered.rb
+++ b/lib/io/stream/buffered.rb
@@ -106,12 +106,14 @@ def sysclose
 			end
 		end
 		
-		if RUBY_VERSION >= "3.3"
+		if RUBY_VERSION >= "3.3" # and RUBY_PLATFORM !~ /win32|mswin|mingw/
 			def syswrite(buffer)
 				return @io.write(buffer)
 			end
 		else
 			def syswrite(buffer)
+				raise IOError, "stream closed" if @io.closed?
+				
 				while true
 					result = @io.write_nonblock(buffer, exception: false)
 					
@@ -133,6 +135,8 @@ def syswrite(buffer)
 		
 		# Reads data from the underlying stream as efficiently as possible.
 		def sysread(size, buffer)
+			raise IOError, "stream closed" if @io.closed?
+			
 			# Come on Ruby, why couldn't this just return `nil`? EOF is not exceptional. Every file has one.
 			while true
 				result = @io.read_nonblock(size, buffer, exception: false)
diff --git a/test/io/stream/buffered.rb b/test/io/stream/buffered.rb
index 2829fe3..f1cc41d 100644
--- a/test/io/stream/buffered.rb
+++ b/test/io/stream/buffered.rb
@@ -321,6 +321,8 @@ def before
 		end
 		
 		it "times out when writing" do
+			skip "#write with timeout not supported on Windows" if RUBY_PLATFORM =~ /win32|mswin|mingw/
+			
 			server.io.timeout = 0.001
 			
 			expect do