diff --git a/command/pr.go b/command/pr.go
index 78c576ffe..d00bfd7bc 100644
--- a/command/pr.go
+++ b/command/pr.go
@@ -219,13 +219,30 @@ func prView(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	apiClient, err := apiClientForContext(ctx)
+	if err != nil {
+		return err
+	}
+
 	var openURL string
 	if len(args) > 0 {
 		if prNumber, err := strconv.Atoi(args[0]); err == nil {
-			// TODO: move URL generation into GitHubRepository
-			openURL = fmt.Sprintf("https://github.com/%s/%s/pull/%d", baseRepo.RepoOwner(), baseRepo.RepoName(), prNumber)
+			pr, err := api.PullRequestByNumber(apiClient, baseRepo, prNumber)
+			if err != nil {
+				return err
+			}
+			openURL = pr.URL
 		} else {
-			return fmt.Errorf("invalid pull request number: '%s'", args[0])
+			prRE := regexp.MustCompile(`^https://github\.com/[^/]+/[^/]+/pull/\d+`)
+			if m := prRE.FindStringSubmatch(args[0]); m != nil {
+				openURL = m[0]
+			} else {
+				pr, err := api.PullRequestForBranch(apiClient, baseRepo, args[0])
+				if err != nil {
+					return err
+				}
+				openURL = pr.URL
+			}
 		}
 	} else {
 		prNumber, branchWithOwner, err := prSelectorForCurrentBranch(ctx)
@@ -236,11 +253,6 @@ func prView(cmd *cobra.Command, args []string) error {
 		if prNumber > 0 {
 			openURL = fmt.Sprintf("https://github.com/%s/%s/pull/%d", baseRepo.RepoOwner(), baseRepo.RepoName(), prNumber)
 		} else {
-			apiClient, err := apiClientForContext(ctx)
-			if err != nil {
-				return err
-			}
-
 			pr, err := api.PullRequestForBranch(apiClient, baseRepo, branchWithOwner)
 			if err != nil {
 				return err
diff --git a/command/pr_test.go b/command/pr_test.go
index 9e0da8331..f271560a5 100644
--- a/command/pr_test.go
+++ b/command/pr_test.go
@@ -251,7 +251,103 @@ func TestPRView_numberArg(t *testing.T) {
 		t.Fatal("expected a command to run")
 	}
 	url := seenCmd.Args[len(seenCmd.Args)-1]
-	if url != "https://github.com/OWNER/REPO/pull/23" {
-		t.Errorf("got: %q", url)
-	}
+	eq(t, url, "https://github.com/OWNER/REPO/pull/23")
+}
+
+func TestPRView_urlArg(t *testing.T) {
+	initBlankContext("OWNER/REPO", "master")
+	initFakeHTTP()
+
+	var seenCmd *exec.Cmd
+	restoreCmd := utils.SetPrepareCmd(func(cmd *exec.Cmd) utils.Runnable {
+		seenCmd = cmd
+		return &outputStub{}
+	})
+	defer restoreCmd()
+
+	output, err := RunCommand(prViewCmd, "pr view https://github.com/OWNER/REPO/pull/23/files")
+	if err != nil {
+		t.Errorf("error running command `pr view`: %v", err)
+	}
+
+	if output == "" {
+		t.Errorf("command output expected got an empty string")
+	}
+
+	if seenCmd == nil {
+		t.Fatal("expected a command to run")
+	}
+	url := seenCmd.Args[len(seenCmd.Args)-1]
+	eq(t, url, "https://github.com/OWNER/REPO/pull/23")
+}
+
+func TestPRView_branchArg(t *testing.T) {
+	initBlankContext("OWNER/REPO", "master")
+	http := initFakeHTTP()
+
+	http.StubResponse(200, bytes.NewBufferString(`
+	{ "data": { "repository": { "pullRequests": { "nodes": [
+		{ "headRefName": "blueberries",
+		  "isCrossRepository": false,
+		  "url": "https://github.com/OWNER/REPO/pull/23" }
+	] } } } }
+	`))
+
+	var seenCmd *exec.Cmd
+	restoreCmd := utils.SetPrepareCmd(func(cmd *exec.Cmd) utils.Runnable {
+		seenCmd = cmd
+		return &outputStub{}
+	})
+	defer restoreCmd()
+
+	output, err := RunCommand(prViewCmd, "pr view blueberries")
+	if err != nil {
+		t.Errorf("error running command `pr view`: %v", err)
+	}
+
+	if output == "" {
+		t.Errorf("command output expected got an empty string")
+	}
+
+	if seenCmd == nil {
+		t.Fatal("expected a command to run")
+	}
+	url := seenCmd.Args[len(seenCmd.Args)-1]
+	eq(t, url, "https://github.com/OWNER/REPO/pull/23")
+}
+
+func TestPRView_branchWithOwnerArg(t *testing.T) {
+	initBlankContext("OWNER/REPO", "master")
+	http := initFakeHTTP()
+
+	http.StubResponse(200, bytes.NewBufferString(`
+	{ "data": { "repository": { "pullRequests": { "nodes": [
+		{ "headRefName": "blueberries",
+		  "isCrossRepository": true,
+		  "headRepositoryOwner": { "login": "hubot" },
+		  "url": "https://github.com/hubot/REPO/pull/23" }
+	] } } } }
+	`))
+
+	var seenCmd *exec.Cmd
+	restoreCmd := utils.SetPrepareCmd(func(cmd *exec.Cmd) utils.Runnable {
+		seenCmd = cmd
+		return &outputStub{}
+	})
+	defer restoreCmd()
+
+	output, err := RunCommand(prViewCmd, "pr view hubot:blueberries")
+	if err != nil {
+		t.Errorf("error running command `pr view`: %v", err)
+	}
+
+	if output == "" {
+		t.Errorf("command output expected got an empty string")
+	}
+
+	if seenCmd == nil {
+		t.Fatal("expected a command to run")
+	}
+	url := seenCmd.Args[len(seenCmd.Args)-1]
+	eq(t, url, "https://github.com/hubot/REPO/pull/23")
 }