diff --git a/lib/percy/client/environment.rb b/lib/percy/client/environment.rb
index 14af83f..b3aa88f 100644
--- a/lib/percy/client/environment.rb
+++ b/lib/percy/client/environment.rb
@@ -204,7 +204,7 @@ def self.parallel_nonce
         when :travis
           ENV['TRAVIS_BUILD_NUMBER']
         when :circle
-          ENV['CIRCLE_BUILD_NUM']
+          ENV['CIRCLE_WORKFLOW_WORKSPACE_ID'] || ENV['CIRCLE_BUILD_NUM']
         when :jenkins
           ENV['BUILD_NUMBER']
         when :codeship
diff --git a/spec/lib/percy/client/environment_spec.rb b/spec/lib/percy/client/environment_spec.rb
index 4ae2066..d6060c0 100644
--- a/spec/lib/percy/client/environment_spec.rb
+++ b/spec/lib/percy/client/environment_spec.rb
@@ -30,6 +30,7 @@ def clear_env_vars
     ENV['CIRCLE_SHA1'] = nil
     ENV['CIRCLE_BRANCH'] = nil
     ENV['CIRCLE_BUILD_NUM'] = nil
+    ENV['CIRCLE_WORKFLOW_WORKSPACE_ID'] = nil
     ENV['CI_PULL_REQUESTS'] = nil
 
     # Unset Codeship vars.
@@ -279,6 +280,16 @@ def clear_env_vars
       expect(Percy::Client::Environment.parallel_total_shards).to be_nil
     end
 
+    context 'in Circle 2.0' do
+      before(:each) do
+        ENV['CIRCLE_WORKFLOW_WORKSPACE_ID'] = 'circle-workflow-workspace-id'
+      end
+
+      it 'has the correct properties' do
+        expect(Percy::Client::Environment.parallel_nonce).to eq('circle-workflow-workspace-id')
+      end
+    end
+
     context 'with a parallel build' do
       before(:each) do
         ENV['CIRCLE_NODE_TOTAL'] = '3'