diff --git a/Library/Homebrew/ast_constants.rb b/Library/Homebrew/ast_constants.rb
index c7a8fa88d7..1de605374d 100644
--- a/Library/Homebrew/ast_constants.rb
+++ b/Library/Homebrew/ast_constants.rb
@@ -32,9 +32,6 @@ FORMULA_COMPONENT_PRECEDENCE_LIST = [
   [{ name: :on_linux, type: :block_call }],
   [{ name: :on_arm, type: :block_call }],
   [{ name: :on_intel, type: :block_call }],
-  *MacOSVersions::SYMBOLS.keys.map do |os_name|
-    [{ name: :"on_#{os_name}", type: :block_call }]
-  end,
   [{ name: :conflicts_with, type: :method_call }],
   [{ name: :skip_clean, type: :method_call }],
   [{ name: :cxxstdlib_check, type: :method_call }],
diff --git a/Library/Homebrew/extend/on_system.rb b/Library/Homebrew/extend/on_system.rb
index 35b81b062d..5ec59cbdfa 100644
--- a/Library/Homebrew/extend/on_system.rb
+++ b/Library/Homebrew/extend/on_system.rb
@@ -89,6 +89,25 @@ module OnSystem
         result
       end
     end
+
+    base.define_method(:on_system) do |linux, macos:, &block|
+      @on_system_blocks_exist = true
+
+      raise ArgumentError, "The first argument to `on_system` must be `:linux`" if linux != :linux
+
+      os_version, or_condition = if macos.to_s.include?("_or_")
+        macos.to_s.split(/_(?=or_)/).map(&:to_sym)
+      else
+        [macos.to_sym, nil]
+      end
+      return if !OnSystem.os_condition_met?(os_version, or_condition) && !OnSystem.os_condition_met?(:linux)
+
+      @called_in_on_system_block = true
+      result = block.call
+      @called_in_on_system_block = false
+
+      result
+    end
   end
 
   sig { params(base: Class).void }
diff --git a/Library/Homebrew/test/formula_spec.rb b/Library/Homebrew/test/formula_spec.rb
index f9e3f93116..e47a197361 100644
--- a/Library/Homebrew/test/formula_spec.rb
+++ b/Library/Homebrew/test/formula_spec.rb
@@ -1538,10 +1538,10 @@ describe Formula do
   describe "#on_macos", :needs_macos do
     let(:f) do
       Class.new(Testball) do
-        @test = 0
         attr_reader :test
 
         def install
+          @test = 0
           on_macos do
             @test = 1
           end
@@ -1561,10 +1561,10 @@ describe Formula do
   describe "#on_linux", :needs_linux do
     let(:f) do
       Class.new(Testball) do
-        @test = 0
         attr_reader :test
 
         def install
+          @test = 0
           on_macos do
             @test = 1
           end
@@ -1581,6 +1581,65 @@ describe Formula do
     end
   end
 
+  describe "#on_system" do
+    after do
+      Homebrew::SimulateSystem.clear
+    end
+
+    let(:f) do
+      Class.new(Testball) do
+        attr_reader :foo
+        attr_reader :bar
+
+        def install
+          @foo = 0
+          @bar = 0
+          on_system :linux, macos: :monterey do
+            @foo = 1
+          end
+          on_system :linux, macos: :big_sur_or_older do
+            @bar = 1
+          end
+        end
+      end.new
+    end
+
+    it "doesn't call code on Ventura", :needs_macos do
+      Homebrew::SimulateSystem.os = :ventura
+      f.brew { f.install }
+      expect(f.foo).to eq(0)
+      expect(f.bar).to eq(0)
+    end
+
+    it "calls code on Linux", :needs_linux do
+      Homebrew::SimulateSystem.os = :linux
+      f.brew { f.install }
+      expect(f.foo).to eq(1)
+      expect(f.bar).to eq(1)
+    end
+
+    it "calls code within `on_system :linux, macos: :monterey` on Monterey", :needs_macos do
+      Homebrew::SimulateSystem.os = :monterey
+      f.brew { f.install }
+      expect(f.foo).to eq(1)
+      expect(f.bar).to eq(0)
+    end
+
+    it "calls code within `on_system :linux, macos: :big_sur_or_older` on Big Sur", :needs_macos do
+      Homebrew::SimulateSystem.os = :big_sur
+      f.brew { f.install }
+      expect(f.foo).to eq(0)
+      expect(f.bar).to eq(1)
+    end
+
+    it "calls code within `on_system :linux, macos: :big_sur_or_older` on Catalina", :needs_macos do
+      Homebrew::SimulateSystem.os = :catalina
+      f.brew { f.install }
+      expect(f.foo).to eq(0)
+      expect(f.bar).to eq(1)
+    end
+  end
+
   describe "on_{os_version} blocks", :needs_macos do
     before do
       Homebrew::SimulateSystem.os = :monterey
@@ -1592,10 +1651,10 @@ describe Formula do
 
     let(:f) do
       Class.new(Testball) do
-        @test = 0
         attr_reader :test
 
         def install
+          @test = 0
           on_monterey :or_newer do
             @test = 1
           end
@@ -1647,10 +1706,10 @@ describe Formula do
 
     let(:f) do
       Class.new(Testball) do
-        @test = 0
         attr_reader :test
 
         def install
+          @test = 0
           on_arm do
             @test = 1
           end
@@ -1674,10 +1733,10 @@ describe Formula do
 
     let(:f) do
       Class.new(Testball) do
-        @test = 0
         attr_reader :test
 
         def install
+          @test = 0
           on_arm do
             @test = 1
           end