diff --git a/Formula/pacparser.rb b/Formula/pacparser.rb
new file mode 100644
index 0000000000000..f1d6369a65fca
--- /dev/null
+++ b/Formula/pacparser.rb
@@ -0,0 +1,108 @@
+class Pacparser < Formula
+  desc "Library to parse proxy auto-config (PAC) files"
+  homepage "https://github.com/pacparser/pacparser"
+  url "https://github.com/pacparser/pacparser/archive/1.3.7.tar.gz"
+  sha256 "575c5d8096b4c842b2af852bbb8bcfde96170b28b49f33249dbe2057a8beea13"
+  head "https://github.com/pacparser/pacparser.git"
+
+  depends_on "python" => :optional
+
+  def install
+    # Disable parallel build due to upstream concurrency issue.
+    # https://github.com/pacparser/pacparser/issues/27
+    ENV.deparallelize
+    ENV["VERSION"] = version
+    Dir.chdir "src"
+    system "make", "install",
+           "PREFIX=#{prefix}"
+    if build.with? "python"
+      system "make", "install-pymod",
+             "EXTRA_ARGS=\"--prefix=#{prefix}\""
+    end
+  end
+
+  test do
+    # example pacfile taken from upstream sources
+    (testpath/"test.pac").write <<-'EOS'.undent
+      function FindProxyForURL(url, host) {
+
+        if ((isPlainHostName(host) ||
+            dnsDomainIs(host, ".manugarg.com")) &&
+            !localHostOrDomainIs(host, "www.manugarg.com"))
+          return "plainhost/.manugarg.com";
+
+        // Return externaldomain if host matches .*\.externaldomain\.com
+        if (/.*\.externaldomain\.com/.test(host))
+          return "externaldomain";
+
+        // Test if DNS resolving is working as intended
+        if (dnsDomainIs(host, ".google.com") &&
+            isResolvable(host))
+          return "isResolvable";
+
+        // Test if DNS resolving is working as intended
+        if (dnsDomainIs(host, ".notresolvabledomainXXX.com") &&
+            !isResolvable(host))
+          return "isNotResolvable";
+
+        if (/^https:\/\/.*$/.test(url))
+          return "secureUrl";
+
+        if (isInNet(myIpAddress(), '10.10.0.0', '255.255.0.0'))
+          return '10.10.0.0';
+
+        if ((typeof(myIpAddressEx) == "function") &&
+            isInNetEx(myIpAddressEx(), '3ffe:8311:ffff/48'))
+          return '3ffe:8311:ffff';
+
+        else
+          return "END-OF-SCRIPT";
+      }
+    EOS
+    # Functional tests from upstream sources
+    test_sets = [
+      {
+        "cmd" => "-c 3ffe:8311:ffff:1:0:0:0:0 -u http://www.somehost.com",
+        "res" => "3ffe:8311:ffff",
+      },
+      {
+        "cmd" => "-c 0.0.0.0 -u http://www.google.co.in",
+        "res" => "END-OF-SCRIPT",
+      },
+      {
+        "cmd" => "-u http://host1",
+        "res" => "plainhost/.manugarg.com",
+      },
+      {
+        "cmd" => "-u http://www1.manugarg.com",
+        "res" => "plainhost/.manugarg.com",
+      },
+      {
+        "cmd" => "-u http://manugarg.externaldomain.com",
+        "res" => "externaldomain",
+      },
+      {
+        "cmd" => "-u http://www.google.com",  ## internet
+        "res" => "isResolvable",              ## requried
+      },
+      {
+        "cmd" => "-u http://www.notresolvabledomainXXX.com",
+        "res" => "isNotResolvable",
+      },
+      {
+        "cmd" => "-u https://www.somehost.com",
+        "res" => "secureUrl",
+      },
+      {
+        "cmd" => "-c 10.10.100.112 -u http://www.somehost.com",
+        "res" => "10.10.0.0",
+      },
+    ]
+    # Loop and execute tests
+    test_sets.each do |t|
+      assert_equal t["res"],
+        shell_output("#{bin}/pactester -p #{testpath}/test.pac " +
+          t["cmd"]).strip
+    end
+  end
+end