diff --git a/cmd/golangorg/server.go b/cmd/golangorg/server.go
index d0191b65..fff2e07f 100644
--- a/cmd/golangorg/server.go
+++ b/cmd/golangorg/server.go
@@ -18,7 +18,6 @@ import (
 	"html/template"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"net/url"
@@ -811,7 +810,7 @@ func (s *seekableFS) Open(name string) (fs.File, error) {
 	if info.IsDir() {
 		return f, nil
 	}
-	data, err := ioutil.ReadAll(f)
+	data, err := io.ReadAll(f)
 	if err != nil {
 		f.Close()
 		return nil, err
diff --git a/internal/gitfs/git.go b/internal/gitfs/git.go
index ff391f38..06325b26 100644
--- a/internal/gitfs/git.go
+++ b/internal/gitfs/git.go
@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"net/http"
 	"strings"
 )
@@ -42,7 +41,7 @@ func (r *Repo) handshake() error {
 	if err != nil {
 		return fmt.Errorf("handshake: %v", err)
 	}
-	data, err := ioutil.ReadAll(resp.Body)
+	data, err := io.ReadAll(resp.Body)
 	if resp.StatusCode != 200 {
 		return fmt.Errorf("handshake: %v\n%s", resp.Status, data)
 	}
@@ -130,7 +129,7 @@ func (r *Repo) refs(prefixes ...string) ([]ref, error) {
 		return nil, fmt.Errorf("refs: %v", err)
 	}
 	defer resp.Body.Close()
-	data, err := ioutil.ReadAll(resp.Body)
+	data, err := io.ReadAll(resp.Body)
 	if resp.StatusCode != 200 {
 		return nil, fmt.Errorf("refs: %v\n%s", resp.Status, data)
 	}
@@ -222,7 +221,7 @@ func (r *Repo) fetch(h Hash) (fs.FS, error) {
 	}
 	defer resp.Body.Close()
 	if resp.StatusCode != 200 {
-		data, _ := ioutil.ReadAll(resp.Body)
+		data, _ := io.ReadAll(resp.Body)
 		return nil, fmt.Errorf("fetch: %v\n%s\n%s", resp.Status, data, hex.Dump(postbody))
 	}
 	if ct := resp.Header.Get("Content-Type"); ct != "application/x-git-upload-pack-result" {
diff --git a/internal/gitfs/git_test.go b/internal/gitfs/git_test.go
index 504ca850..33546f04 100644
--- a/internal/gitfs/git_test.go
+++ b/internal/gitfs/git_test.go
@@ -6,7 +6,7 @@ package gitfs
 
 import (
 	"io/fs"
-	"io/ioutil"
+	"os"
 	"testing"
 )
 
@@ -49,7 +49,7 @@ func TestGitHub(t *testing.T) {
 }
 
 func TestPack(t *testing.T) {
-	data, err := ioutil.ReadFile("testdata/scratch.pack")
+	data, err := os.ReadFile("testdata/scratch.pack")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/internal/gitfs/pack.go b/internal/gitfs/pack.go
index 6913312a..7b3ba9cb 100644
--- a/internal/gitfs/pack.go
+++ b/internal/gitfs/pack.go
@@ -10,7 +10,7 @@ import (
 	"crypto/sha1"
 	"encoding/binary"
 	"fmt"
-	"io/ioutil"
+	"io"
 )
 
 // unpack parses data, which is a Git pack-formatted archive,
@@ -142,7 +142,7 @@ func unpackObject(s *store, objs []byte, off int) (typ objType, h Hash, content
 	if err != nil {
 		return fail(fmt.Errorf("invalid object deflate: %v", err))
 	}
-	data, err := ioutil.ReadAll(zr)
+	data, err := io.ReadAll(zr)
 	if err != nil {
 		return fail(fmt.Errorf("invalid object: bad deflate: %v", err))
 	}
diff --git a/internal/pkgdoc/doc.go b/internal/pkgdoc/doc.go
index e915b70a..ef1712a3 100644
--- a/internal/pkgdoc/doc.go
+++ b/internal/pkgdoc/doc.go
@@ -17,7 +17,6 @@ import (
 	"go/token"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"net/url"
@@ -181,7 +180,7 @@ func (d *docs) open(dir string, mode mode, goos, goarch string) *Page {
 		if err != nil {
 			return nil, err
 		}
-		return ioutil.NopCloser(bytes.NewReader(data)), nil
+		return io.NopCloser(bytes.NewReader(data)), nil
 	}
 
 	// Make the syscall/js package always visible by default.
diff --git a/internal/play/proxy.go b/internal/play/proxy.go
index 1b3e24d2..069d4a8e 100644
--- a/internal/play/proxy.go
+++ b/internal/play/proxy.go
@@ -10,7 +10,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"regexp"
@@ -117,7 +116,7 @@ func makeCompileRequest(ctx context.Context, backend string, req *Request, res *
 	defer r.Body.Close()
 
 	if r.StatusCode != http.StatusOK {
-		b, _ := ioutil.ReadAll(r.Body)
+		b, _ := io.ReadAll(r.Body)
 		return fmt.Errorf("bad status: %v body:\n%s", r.Status, b)
 	}
 
diff --git a/internal/screentest/screentest.go b/internal/screentest/screentest.go
index fe896819..841fafaa 100644
--- a/internal/screentest/screentest.go
+++ b/internal/screentest/screentest.go
@@ -123,7 +123,6 @@ import (
 	"image/png"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"net/url"
@@ -742,9 +741,9 @@ func (tc *testcase) screenshot(ctx context.Context, url, file string,
 			return nil, fmt.Errorf("object.NewReader(ctx): %w", err)
 		} else if err == nil {
 			defer r.Close()
-			data, err = ioutil.ReadAll(r)
+			data, err = io.ReadAll(r)
 			if err != nil {
-				return nil, fmt.Errorf("ioutil.ReadAll(...): %w", err)
+				return nil, fmt.Errorf("io.ReadAll(...): %w", err)
 			}
 		}
 	} else if cache {
diff --git a/internal/tmplfunc/tmpl.go b/internal/tmplfunc/tmpl.go
index 3bca424d..d3432e4b 100644
--- a/internal/tmplfunc/tmpl.go
+++ b/internal/tmplfunc/tmpl.go
@@ -82,7 +82,7 @@ package tmplfunc
 import (
 	"fmt"
 	"io/fs"
-	"io/ioutil"
+	"os"
 	"path"
 	"path/filepath"
 
@@ -234,7 +234,7 @@ func MustParseGlob(t Template, pattern string) {
 
 func readFileOS(file string) (name string, b []byte, err error) {
 	name = filepath.Base(file)
-	b, err = ioutil.ReadFile(file)
+	b, err = os.ReadFile(file)
 	return
 }
 
diff --git a/internal/webtest/webtest.go b/internal/webtest/webtest.go
index ef77276f..12222fbe 100644
--- a/internal/webtest/webtest.go
+++ b/internal/webtest/webtest.go
@@ -153,10 +153,10 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
+	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
@@ -244,7 +244,7 @@ func test(t *testing.T, glob string, do func(*case_) error) {
 	}
 	for _, file := range files {
 		t.Run(filepath.Base(file), func(t *testing.T) {
-			data, err := ioutil.ReadFile(file)
+			data, err := os.ReadFile(file)
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -345,7 +345,7 @@ func (c *case_) runServer(addr string) error {
 	if err != nil {
 		return fmt.Errorf("%s:%d: %s %s: %s", c.file, c.line, c.method, c.url, err)
 	}
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	resp.Body.Close()
 	if err != nil {
 		return fmt.Errorf("%s:%d: %s %s: reading body: %s", c.file, c.line, c.method, c.url, err)
diff --git a/internal/webtest/webtest_test.go b/internal/webtest/webtest_test.go
index cb3e2b01..4bb23722 100644
--- a/internal/webtest/webtest_test.go
+++ b/internal/webtest/webtest_test.go
@@ -6,8 +6,8 @@ package webtest
 
 import (
 	"fmt"
-	"io/ioutil"
 	"net/http"
+	"os"
 	"path/filepath"
 	"strings"
 	"testing"
@@ -43,7 +43,7 @@ func testWebtest(t *testing.T, glob string, do func(*case_) error) {
 	}
 	for _, file := range files {
 		t.Run(filepath.Base(file), func(t *testing.T) {
-			data, err := ioutil.ReadFile(file)
+			data, err := os.ReadFile(file)
 			if err != nil {
 				t.Fatal(err)
 			}