diff --git a/github/repos_commits.go b/github/repos_commits.go
index 5d3784a3d71..06210c579c7 100644
--- a/github/repos_commits.go
+++ b/github/repos_commits.go
@@ -9,6 +9,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"net/url"
 	"time"
 )
 
@@ -222,9 +223,11 @@ func (s *RepositoriesService) GetCommitSHA1(ctx context.Context, owner, repo, re
 
 // CompareCommits compares a range of commits with each other.
 //
+// The url query string is escaped before making the request.
+//
 // GitHub API docs: https://docs.github.com/en/rest/reference/repos/#compare-two-commits
-func (s *RepositoriesService) CompareCommits(ctx context.Context, owner, repo string, base, head string) (*CommitsComparison, *Response, error) {
-	u := fmt.Sprintf("repos/%v/%v/compare/%v...%v", owner, repo, base, head)
+func (s *RepositoriesService) CompareCommits(ctx context.Context, owner, repo, base, head string) (*CommitsComparison, *Response, error) {
+	u := url.QueryEscape(fmt.Sprintf("repos/%v/%v/compare/%v...%v", owner, repo, base, head))
 
 	req, err := s.client.NewRequest("GET", u, nil)
 	if err != nil {
diff --git a/github/repos_commits_test.go b/github/repos_commits_test.go
index 6da964fec56..489092ae7d7 100644
--- a/github/repos_commits_test.go
+++ b/github/repos_commits_test.go
@@ -9,6 +9,7 @@ import (
 	"context"
 	"fmt"
 	"net/http"
+	"net/url"
 	"reflect"
 	"strings"
 	"testing"
@@ -305,99 +306,118 @@ func TestRepositoriesService_CompareCommits(t *testing.T) {
 	client, mux, _, teardown := setup()
 	defer teardown()
 
-	mux.HandleFunc("/repos/o/r/compare/b...h", func(w http.ResponseWriter, r *http.Request) {
-		testMethod(t, r, "GET")
-		fmt.Fprintf(w, `{
-		  "base_commit": {
-		    "sha": "s",
-		    "commit": {
-		      "author": { "name": "n" },
-		      "committer": { "name": "n" },
-		      "message": "m",
-		      "tree": { "sha": "t" }
-		    },
-		    "author": { "login": "l" },
-		    "committer": { "login": "l" },
-		    "parents": [ { "sha": "s" } ]
-		  },
-		  "status": "s",
-		  "ahead_by": 1,
-		  "behind_by": 2,
-		  "total_commits": 1,
-		  "commits": [
-		    {
-		      "sha": "s",
-		      "commit": { "author": { "name": "n" } },
-		      "author": { "login": "l" },
-		      "committer": { "login": "l" },
-		      "parents": [ { "sha": "s" } ]
-		    }
-		  ],
-		  "files": [ { "filename": "f" } ],
-		  "html_url":      "https://github.com/o/r/compare/b...h",
-		  "permalink_url": "https://github.com/o/r/compare/o:bbcd538c8e72b8c175046e27cc8f907076331401...o:0328041d1152db8ae77652d1618a02e57f745f17",
-		  "diff_url":      "https://github.com/o/r/compare/b...h.diff",
-		  "patch_url":     "https://github.com/o/r/compare/b...h.patch",
-		  "url":           "https://api.github.com/repos/o/r/compare/b...h"
-		}`)
-	})
+	cases := []struct {
+		name string
+		b    string
+		h    string
+	}{
+		{name: "case 1", b: "b", h: "h"},
+		{name: "case 2", b: "#b#", h: "#h#"},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			b := url.QueryEscape(c.b)
+			h := url.QueryEscape(c.h)
+
+			u := fmt.Sprintf("/repos/o/r/compare/%v...%v", c.b, c.h)
+
+			mux.HandleFunc(u, func(w http.ResponseWriter, r *http.Request) {
+				testMethod(t, r, "GET")
+				fmt.Fprintf(w, `{
+				  "base_commit": {
+					"sha": "s",
+					"commit": {
+					  "author": { "name": "n" },
+					  "committer": { "name": "n" },
+					  "message": "m",
+					  "tree": { "sha": "t" }
+					},
+					"author": { "login": "l" },
+					"committer": { "login": "l" },
+					"parents": [ { "sha": "s" } ]
+				  },
+				  "status": "s",
+				  "ahead_by": 1,
+				  "behind_by": 2,
+				  "total_commits": 1,
+				  "commits": [
+					{
+					  "sha": "s",
+					  "commit": { "author": { "name": "n" } },
+					  "author": { "login": "l" },
+					  "committer": { "login": "l" },
+					  "parents": [ { "sha": "s" } ]
+					}
+				  ],
+				  "files": [ { "filename": "f" } ],
+				  "html_url":      "https://github.com/o/r/compare/%[1]v...%[2]v",
+				  "permalink_url": "https://github.com/o/r/compare/o:bbcd538c8e72b8c175046e27cc8f907076331401...o:0328041d1152db8ae77652d1618a02e57f745f17",
+				  "diff_url":      "https://github.com/o/r/compare/%[1]v...%[2]v.diff",
+				  "patch_url":     "https://github.com/o/r/compare/%[1]v...%[2]v.patch",
+				  "url":           "https://api.github.com/repos/o/r/compare/%[1]v...%[2]v"
+				}`, b, h)
+			})
 
-	got, _, err := client.Repositories.CompareCommits(context.Background(), "o", "r", "b", "h")
-	if err != nil {
-		t.Errorf("Repositories.CompareCommits returned error: %v", err)
-	}
+			got, _, err := client.Repositories.CompareCommits(context.Background(), "o", "r", c.b, c.h)
+			if err != nil {
+				t.Errorf("Repositories.CompareCommits returned error: %v", err)
+			}
 
-	want := &CommitsComparison{
-		BaseCommit: &RepositoryCommit{
-			SHA: String("s"),
-			Commit: &Commit{
-				Author:    &CommitAuthor{Name: String("n")},
-				Committer: &CommitAuthor{Name: String("n")},
-				Message:   String("m"),
-				Tree:      &Tree{SHA: String("t")},
-			},
-			Author:    &User{Login: String("l")},
-			Committer: &User{Login: String("l")},
-			Parents: []*Commit{
-				{
+			want := &CommitsComparison{
+				BaseCommit: &RepositoryCommit{
 					SHA: String("s"),
+					Commit: &Commit{
+						Author:    &CommitAuthor{Name: String("n")},
+						Committer: &CommitAuthor{Name: String("n")},
+						Message:   String("m"),
+						Tree:      &Tree{SHA: String("t")},
+					},
+					Author:    &User{Login: String("l")},
+					Committer: &User{Login: String("l")},
+					Parents: []*Commit{
+						{
+							SHA: String("s"),
+						},
+					},
 				},
-			},
-		},
-		Status:       String("s"),
-		AheadBy:      Int(1),
-		BehindBy:     Int(2),
-		TotalCommits: Int(1),
-		Commits: []*RepositoryCommit{
-			{
-				SHA: String("s"),
-				Commit: &Commit{
-					Author: &CommitAuthor{Name: String("n")},
-				},
-				Author:    &User{Login: String("l")},
-				Committer: &User{Login: String("l")},
-				Parents: []*Commit{
+				Status:       String("s"),
+				AheadBy:      Int(1),
+				BehindBy:     Int(2),
+				TotalCommits: Int(1),
+				Commits: []*RepositoryCommit{
 					{
 						SHA: String("s"),
+						Commit: &Commit{
+							Author: &CommitAuthor{Name: String("n")},
+						},
+						Author:    &User{Login: String("l")},
+						Committer: &User{Login: String("l")},
+						Parents: []*Commit{
+							{
+								SHA: String("s"),
+							},
+						},
 					},
 				},
-			},
-		},
-		Files: []*CommitFile{
-			{
-				Filename: String("f"),
-			},
-		},
-		HTMLURL:      String("https://github.com/o/r/compare/b...h"),
-		PermalinkURL: String("https://github.com/o/r/compare/o:bbcd538c8e72b8c175046e27cc8f907076331401...o:0328041d1152db8ae77652d1618a02e57f745f17"),
-		DiffURL:      String("https://github.com/o/r/compare/b...h.diff"),
-		PatchURL:     String("https://github.com/o/r/compare/b...h.patch"),
-		URL:          String("https://api.github.com/repos/o/r/compare/b...h"),
-	}
+				Files: []*CommitFile{
+					{
+						Filename: String("f"),
+					},
+				},
+				HTMLURL:      String(fmt.Sprintf("https://github.com/o/r/compare/%v...%v", b, h)),
+				PermalinkURL: String("https://github.com/o/r/compare/o:bbcd538c8e72b8c175046e27cc8f907076331401...o:0328041d1152db8ae77652d1618a02e57f745f17"),
+				DiffURL:      String(fmt.Sprintf("https://github.com/o/r/compare/%v...%v.diff", b, h)),
+				PatchURL:     String(fmt.Sprintf("https://github.com/o/r/compare/%v...%v.patch", b, h)),
+				URL:          String(fmt.Sprintf("https://api.github.com/repos/o/r/compare/%v...%v", b, h)),
+			}
 
-	if !reflect.DeepEqual(got, want) {
-		t.Errorf("Repositories.CompareCommits returned \n%+v, want \n%+v", got, want)
+			if !reflect.DeepEqual(got, want) {
+				t.Errorf("Repositories.CompareCommits returned \n%+v, want \n%+v", got, want)
+			}
+		})
 	}
+
 }
 
 func TestRepositoriesService_CompareCommitsRaw_diff(t *testing.T) {