diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index bb118f400..ab1d23db8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,20 +6,24 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}-latest
     timeout-minutes: 10
 
     strategy:
       fail-fast: false
       matrix:
         ruby: [2.3, 2.4, 2.5, 2.6, 2.7, '3.0', 3.1, 3.2, 3.3, jruby, truffleruby]
+        os: [ubuntu]
+        include:
+          - ruby: 3.3
+            os: windows
 
     env:
       JAVA_OPTS: '-Xmx1024m'
       RUBYOPT: '-w'
       JRUBY_OPTS: '--dev'
 
-    name: "Tests: Ruby ${{ matrix.ruby }}"
+    name: "Tests: Ruby ${{ matrix.ruby }} - ${{ matrix.os }}"
     steps:
     - name: Clone Repo
       uses: actions/checkout@v4
diff --git a/lib/concurrent-ruby/concurrent/utility/processor_counter.rb b/lib/concurrent-ruby/concurrent/utility/processor_counter.rb
index e31808722..d5274620e 100644
--- a/lib/concurrent-ruby/concurrent/utility/processor_counter.rb
+++ b/lib/concurrent-ruby/concurrent/utility/processor_counter.rb
@@ -68,10 +68,20 @@ def compute_physical_processor_count
                 end
                 cores.count
               when /mswin|mingw/
-                require 'win32ole'
-                result_set = WIN32OLE.connect("winmgmts://").ExecQuery(
-                  "select NumberOfCores from Win32_Processor")
-                result_set.to_enum.collect(&:NumberOfCores).reduce(:+)
+                # Get-CimInstance introduced in PowerShell 3 or earlier: https://learn.microsoft.com/en-us/previous-versions/powershell/module/cimcmdlets/get-ciminstance?view=powershell-3.0
+                result = run('powershell -command "Get-CimInstance -ClassName Win32_Processor  | Select-Object -Property NumberOfCores"')
+                if !result || $?.exitstatus != 0
+                  # fallback to deprecated wmic for older systems
+                  result = run("wmic cpu get NumberOfCores")
+                end
+                if !result || $?.exitstatus != 0
+                  # Bail out if both commands returned something unexpected
+                  processor_count
+                else
+                  # powershell: "\nNumberOfCores\n-------------\n            4\n\n\n" 
+                  # wmic:       "NumberOfCores  \n\n4              \n\n\n\n"
+                  result.scan(/\d+/).map(&:to_i).reduce(:+)
+                end
               else
                 processor_count
               end
@@ -81,6 +91,11 @@ def compute_physical_processor_count
         return 1
       end
 
+      def run(command)
+        IO.popen(command, &:read)
+      rescue Errno::ENOENT
+      end
+
       def compute_cpu_quota
         if RbConfig::CONFIG["target_os"].include?("linux")
           if File.exist?("/sys/fs/cgroup/cpu.max")
diff --git a/spec/concurrent/channel/integration_spec.rb b/spec/concurrent/channel/integration_spec.rb
index 01f490dc9..4d4c073ee 100644
--- a/spec/concurrent/channel/integration_spec.rb
+++ b/spec/concurrent/channel/integration_spec.rb
@@ -68,7 +68,7 @@
     end
 
     specify 'default-selection.rb' do
-      skip('flaky') if Concurrent.on_jruby? || Concurrent.on_truffleruby?
+      skip('flaky') if Concurrent.on_jruby? || Concurrent.on_truffleruby? || Concurrent.on_windows?
 expected = <<-STDOUT
     .
     .
diff --git a/spec/concurrent/promises_spec.rb b/spec/concurrent/promises_spec.rb
index d89ce309f..2aa88fdfa 100644
--- a/spec/concurrent/promises_spec.rb
+++ b/spec/concurrent/promises_spec.rb
@@ -758,6 +758,7 @@ def behaves_as_delay(delay, value)
   describe 'value!' do
     %w[with without].each do |timeout|
       it "does not return spuriously #{timeout} timeout" do
+        skip "SIGHUP not supported" if Concurrent.on_windows?
         # https://github.com/ruby-concurrency/concurrent-ruby/issues/1015
         trapped = false
         original_handler = Signal.trap(:SIGHUP) { trapped = true }