diff --git a/github/github-accessors.go b/github/github-accessors.go
index 8598de67f6e..69547c4f09a 100644
--- a/github/github-accessors.go
+++ b/github/github-accessors.go
@@ -7220,6 +7220,22 @@ func (p *PageStats) GetTotalPages() int {
 	return *p.TotalPages
 }
 
+// GetCNAME returns the CNAME field if it's non-nil, zero value otherwise.
+func (p *PagesUpdate) GetCNAME() string {
+	if p == nil || p.CNAME == nil {
+		return ""
+	}
+	return *p.CNAME
+}
+
+// GetSource returns the Source field if it's non-nil, zero value otherwise.
+func (p *PagesUpdate) GetSource() string {
+	if p == nil || p.Source == nil {
+		return ""
+	}
+	return *p.Source
+}
+
 // GetHook returns the Hook field.
 func (p *PingEvent) GetHook() *Hook {
 	if p == nil {
diff --git a/github/repos_pages.go b/github/repos_pages.go
index ff8d2d55b9c..58826527d9d 100644
--- a/github/repos_pages.go
+++ b/github/repos_pages.go
@@ -75,6 +75,35 @@ func (s *RepositoriesService) EnablePages(ctx context.Context, owner, repo strin
 	return enable, resp, nil
 }
 
+// PagesUpdate sets up parameters needed to update a GitHub Pages site.
+type PagesUpdate struct {
+	// CNAME represents a custom domain for the repository.
+	// Leaving CNAME empty will remove the custom domain.
+	CNAME *string `json:"cname"`
+	// Source must include the branch name, and may optionally specify the subdirectory "/docs".
+	// Possible values are: "gh-pages", "master", and "master /docs".
+	Source *string `json:"source,omitempty"`
+}
+
+// UpdatePages updates GitHub Pages for the named repo.
+//
+// GitHub API docs: https://developer.github.com/v3/repos/pages/#update-information-about-a-pages-site
+func (s *RepositoriesService) UpdatePages(ctx context.Context, owner, repo string, opts *PagesUpdate) (*Response, error) {
+	u := fmt.Sprintf("repos/%v/%v/pages", owner, repo)
+
+	req, err := s.client.NewRequest("PUT", u, opts)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := s.client.Do(ctx, req, nil)
+	if err != nil {
+		return resp, err
+	}
+
+	return resp, nil
+}
+
 // DisablePages disables GitHub Pages for the named repo.
 //
 // GitHub API docs: https://developer.github.com/v3/repos/pages/#disable-a-pages-site
diff --git a/github/repos_pages_test.go b/github/repos_pages_test.go
index 8fe38eb3e24..b2aa272939a 100644
--- a/github/repos_pages_test.go
+++ b/github/repos_pages_test.go
@@ -6,9 +6,11 @@
 package github
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
+	"io/ioutil"
 	"net/http"
 	"reflect"
 	"testing"
@@ -52,6 +54,62 @@ func TestRepositoriesService_EnablePages(t *testing.T) {
 	}
 }
 
+func TestRepositoriesService_UpdatePages(t *testing.T) {
+	client, mux, _, teardown := setup()
+	defer teardown()
+
+	input := &PagesUpdate{
+		CNAME:  String("www.my-domain.com"),
+		Source: String("gh-pages"),
+	}
+
+	mux.HandleFunc("/repos/o/r/pages", func(w http.ResponseWriter, r *http.Request) {
+		v := new(PagesUpdate)
+		json.NewDecoder(r.Body).Decode(v)
+
+		testMethod(t, r, "PUT")
+		want := &PagesUpdate{CNAME: String("www.my-domain.com"), Source: String("gh-pages")}
+		if !reflect.DeepEqual(v, want) {
+			t.Errorf("Request body = %+v, want %+v", v, want)
+		}
+
+		fmt.Fprint(w, `{"cname":"www.my-domain.com","source":"gh-pages"}`)
+	})
+
+	_, err := client.Repositories.UpdatePages(context.Background(), "o", "r", input)
+	if err != nil {
+		t.Errorf("Repositories.UpdatePages returned error: %v", err)
+	}
+}
+
+func TestRepositoriesService_UpdatePages_NullCNAME(t *testing.T) {
+	client, mux, _, teardown := setup()
+	defer teardown()
+
+	input := &PagesUpdate{
+		Source: String("gh-pages"),
+	}
+
+	mux.HandleFunc("/repos/o/r/pages", func(w http.ResponseWriter, r *http.Request) {
+		got, err := ioutil.ReadAll(r.Body)
+		if err != nil {
+			t.Fatalf("unable to read body: %v", err)
+		}
+
+		want := []byte(`{"cname":null,"source":"gh-pages"}` + "\n")
+		if !bytes.Equal(got, want) {
+			t.Errorf("Request body = %+v, want %+v", got, want)
+		}
+
+		fmt.Fprint(w, `{"cname":null,"source":"gh-pages"}`)
+	})
+
+	_, err := client.Repositories.UpdatePages(context.Background(), "o", "r", input)
+	if err != nil {
+		t.Errorf("Repositories.UpdatePages returned error: %v", err)
+	}
+}
+
 func TestRepositoriesService_DisablePages(t *testing.T) {
 	client, mux, _, teardown := setup()
 	defer teardown()