diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
index 674850e..cfcb690 100644
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+## Customerio 5.1.0 - May 5, 2023
+### Added
+- Added `send_push` to `APIClient` and `SendPushRequest` to support sending transactional push notifications.
+
 ## Customerio 4.3.1 - January 5, 2023
 ### Added
 - Added the `disable_css_preprocessing` and `language` optional fields to send request
diff --git a/README.md b/README.md
index 0a15fb2..b438fda 100644
--- a/README.md
+++ b/README.md
@@ -217,7 +217,9 @@ $customerio.unsuppress(5)
 
 ### Send Transactional Messages
 
-To use the Customer.io [Transactional API](https://customer.io/docs/transactional-api), create an instance of the API client using an [app key](https://customer.io/docs/managing-credentials#app-api-keys).
+To use the Customer.io [Transactional API](https://customer.io/docs/transactional-api), create an instance of the API client using an [app key](https://customer.io/docs/managing-credentials#app-api-keys) and create a request object of your message type.
+
+#### Email
 
 Create a new `SendEmailRequest` object containing:
 
@@ -262,6 +264,44 @@ rescue Customerio::InvalidResponse => e
 end
 ```
 
+#### Push
+
+Create a new `SendPushRequest` object containing:
+
+* `transactional_message_id`: the ID or trigger name of the transactional message you want to send.
+* an `identifiers` object containing the `id` or `email` of your recipient. If the profile does not exist, Customer.io creates it.
+
+Use `send_push` referencing your request to send a transactional message. [Learn more about transactional messages and `SendPushRequest` properties](https://customer.io/docs/transactional-api).
+
+
+```ruby
+require "customerio"
+
+client = Customerio::APIClient.new("your API key", region: Customerio::Regions::US)
+
+request = Customerio::SendPushRequest.new(
+  transactional_message_id: "3",
+  message_data: {
+    name: "Person",
+    items: {
+      name: "shoes",
+      price: "59.99",
+    },
+    products: [],
+  },
+  identifiers: {
+    id: "2",
+  },
+)
+
+begin
+  response = client.send_push(request)
+  puts response
+rescue Customerio::InvalidResponse => e
+  puts e.code, e.message
+end
+```
+
 ## Contributing
 
 1. Fork it
diff --git a/lib/customerio.rb b/lib/customerio.rb
index 95f33f6..e824c5b 100644
--- a/lib/customerio.rb
+++ b/lib/customerio.rb
@@ -5,6 +5,7 @@ module Customerio
   require "customerio/base_client"
   require "customerio/client"
   require "customerio/requests/send_email_request"
+  require "customerio/requests/send_push_request"
   require "customerio/api"
   require "customerio/param_encoder"
 end
diff --git a/lib/customerio/api.rb b/lib/customerio/api.rb
index 2530f76..97394b1 100644
--- a/lib/customerio/api.rb
+++ b/lib/customerio/api.rb
@@ -26,10 +26,29 @@ def send_email(req)
       end
     end
 
+    def send_push(req)
+      raise "request must be an instance of Customerio::SendPushRequest" unless req.is_a?(Customerio::SendPushRequest)
+      response = @client.request(:post, send_push_path, req.message)
+
+      case response
+      when Net::HTTPSuccess then
+        JSON.parse(response.body)
+      when Net::HTTPBadRequest then
+        json = JSON.parse(response.body)
+        raise Customerio::InvalidResponse.new(response.code, json['meta']['error'], response)
+      else
+        raise InvalidResponse.new(response.code, response.body)
+      end
+    end
+
     private
 
     def send_email_path
       "/v1/send/email"
     end
+
+    def send_push_path
+      "/v1/send/push"
+    end
   end
 end
diff --git a/lib/customerio/requests/send_push_request.rb b/lib/customerio/requests/send_push_request.rb
new file mode 100644
index 0000000..1224c23
--- /dev/null
+++ b/lib/customerio/requests/send_push_request.rb
@@ -0,0 +1,36 @@
+module Customerio
+  class SendPushRequest
+    attr_reader :message
+
+    def initialize(opts)
+      @message = opts.delete_if { |field| invalid_field?(field) }
+      @message[:custom_device] = opts[:device] if opts[:device]
+    end
+
+    private
+
+    REQUIRED_FIELDS = %i(transactional_message_id identifiers)
+
+    OPTIONAL_FIELDS = %i(
+      to
+      title
+      message
+      disable_message_retention
+      send_to_unsubscribed
+      queue_draft
+      message_data
+      send_at
+      language
+      image_url
+      link
+      sound
+      custom_data
+      device
+      custom_device
+    )
+
+    def invalid_field?(field)
+      !REQUIRED_FIELDS.include?(field) && !OPTIONAL_FIELDS.include?(field)
+    end
+  end
+end
diff --git a/lib/customerio/version.rb b/lib/customerio/version.rb
index becdd6e..d5e7a94 100644
--- a/lib/customerio/version.rb
+++ b/lib/customerio/version.rb
@@ -1,3 +1,3 @@
 module Customerio
-  VERSION = "5.0.0"
+  VERSION = "5.1.0"
 end
diff --git a/spec/api_client_spec.rb b/spec/api_client_spec.rb
index a7a0db6..fac44ab 100644
--- a/spec/api_client_spec.rb
+++ b/spec/api_client_spec.rb
@@ -6,7 +6,7 @@
 describe Customerio::APIClient do
   let(:app_key) { "appkey" }
 
-  let(:client)   { Customerio::APIClient.new(app_key) }
+  let(:client) { Customerio::APIClient.new(app_key) }
   let(:response) { double("Response", code: 200) }
 
   def api_uri(path)
@@ -169,4 +169,87 @@ def json(data)
       req.message[:attachments].should eq({ "test" => Base64.strict_encode64("test-content") })
     end
   end
+
+  describe "#send_push" do
+    it "sends a POST request to the /api/send/push path" do
+      req = Customerio::SendPushRequest.new(
+        identifiers: {
+          id: 'c1',
+        },
+        transactional_message_id: 1,
+      )
+
+      stub_request(:post, api_uri('/v1/send/push'))
+        .with(headers: request_headers, body: req.message)
+        .to_return(status: 200, body: { delivery_id: 1 }.to_json, headers: {})
+
+      client.send_push(req).should eq({ "delivery_id" => 1 })
+    end
+
+    it "handles validation failures (400)" do
+      req = Customerio::SendPushRequest.new(
+        identifiers: {
+          id: 'c1',
+        },
+        transactional_message_id: 1,
+      )
+
+      err_json = { meta: { error: "example error" } }.to_json
+
+      stub_request(:post, api_uri('/v1/send/push'))
+        .with(headers: request_headers, body: req.message)
+        .to_return(status: 400, body: err_json, headers: {})
+
+      lambda { client.send_push(req) }.should(
+        raise_error(Customerio::InvalidResponse) { |error|
+          error.message.should eq "example error"
+          error.code.should eq "400"
+        }
+      )
+    end
+
+    it "handles other failures (5xx)" do
+      req = Customerio::SendPushRequest.new(
+        identifiers: {
+          id: 'c1',
+        },
+        transactional_message_id: 1,
+      )
+
+      stub_request(:post, api_uri('/v1/send/push'))
+        .with(headers: request_headers, body: req.message)
+        .to_return(status: 500, body: "Server unavailable", headers: {})
+
+      lambda { client.send_push(req) }.should(
+        raise_error(Customerio::InvalidResponse) { |error|
+          error.message.should eq "Server unavailable"
+          error.code.should eq "500"
+        }
+      )
+    end
+
+    it "sets custom_device correctly if device present in req" do
+      req = Customerio::SendPushRequest.new(
+        identifiers: {
+          id: 'c1',
+        },
+        transactional_message_id: 1,
+        device: {
+          platform: 'ios',
+          token: 'sample-token',
+        }
+      )
+
+      req.message[:custom_device].should eq({
+        platform: 'ios',
+        token: 'sample-token',
+      })
+
+      stub_request(:post, api_uri('/v1/send/push'))
+        .with(headers: request_headers, body: req.message)
+        .to_return(status: 200, body: { delivery_id: 2 }.to_json, headers: {})
+
+      client.send_push(req).should eq({ "delivery_id" => 2 })
+    end
+  end
 end