diff --git a/cmd/testscript/main.go b/cmd/testscript/main.go
index 6b2629d6..f91d5682 100644
--- a/cmd/testscript/main.go
+++ b/cmd/testscript/main.go
@@ -8,7 +8,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -72,7 +72,7 @@ func mainerr() (retErr error) {
 		return err
 	}
 
-	td, err := ioutil.TempDir("", "testscript")
+	td, err := os.MkdirTemp("", "testscript")
 	if err != nil {
 		return fmt.Errorf("unable to create temp dir: %v", err)
 	}
@@ -171,7 +171,7 @@ func (tr *testRunner) run(runDir, filename string) error {
 	}
 
 	if filename == "-" {
-		byts, err := ioutil.ReadAll(os.Stdin)
+		byts, err := io.ReadAll(os.Stdin)
 		if err != nil {
 			return fmt.Errorf("failed to read from stdin: %v", err)
 		}
@@ -204,7 +204,7 @@ func (tr *testRunner) run(runDir, filename string) error {
 
 	scriptFile := filepath.Join(runDir, "script.txtar")
 
-	if err := ioutil.WriteFile(scriptFile, txtar.Format(&script), 0o666); err != nil {
+	if err := os.WriteFile(scriptFile, txtar.Format(&script), 0o666); err != nil {
 		return fmt.Errorf("failed to write script for %v: %v", renderFilename(filename), err)
 	}
 
@@ -309,7 +309,7 @@ func (tr *testRunner) run(runDir, filename string) error {
 		// Parse the (potentially) updated scriptFile as an archive, then merge
 		// with the original archive, retaining order.  Then write the archive
 		// back to the source file
-		source, err := ioutil.ReadFile(scriptFile)
+		source, err := os.ReadFile(scriptFile)
 		if err != nil {
 			return fmt.Errorf("failed to read from script file %v for -update: %v", scriptFile, err)
 		}
@@ -323,7 +323,7 @@ func (tr *testRunner) run(runDir, filename string) error {
 				ar.Files[i] = newF
 			}
 		}
-		if err := ioutil.WriteFile(filename, txtar.Format(ar), 0o666); err != nil {
+		if err := os.WriteFile(filename, txtar.Format(ar), 0o666); err != nil {
 			return fmt.Errorf("failed to write script back to %v for -update: %v", renderFilename(filename), err)
 		}
 	}
diff --git a/dirhash/hash_test.go b/dirhash/hash_test.go
index db77c39f..c4f7c227 100644
--- a/dirhash/hash_test.go
+++ b/dirhash/hash_test.go
@@ -10,7 +10,6 @@ import (
 	"encoding/base64"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -29,7 +28,7 @@ func htop(k string, s string) string {
 func TestHash1(t *testing.T) {
 	files := []string{"xyz", "abc"}
 	open := func(name string) (io.ReadCloser, error) {
-		return ioutil.NopCloser(strings.NewReader("data for " + name)), nil
+		return io.NopCloser(strings.NewReader("data for " + name)), nil
 	}
 	want := htop("h1", fmt.Sprintf("%s  %s\n%s  %s\n", h("data for abc"), "abc", h("data for xyz"), "xyz"))
 	out, err := Hash1(files, open)
@@ -47,15 +46,15 @@ func TestHash1(t *testing.T) {
 }
 
 func TestHashDir(t *testing.T) {
-	dir, err := ioutil.TempDir("", "dirhash-test-")
+	dir, err := os.MkdirTemp("", "dirhash-test-")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(dir)
-	if err := ioutil.WriteFile(filepath.Join(dir, "xyz"), []byte("data for xyz"), 0o666); err != nil {
+	if err := os.WriteFile(filepath.Join(dir, "xyz"), []byte("data for xyz"), 0o666); err != nil {
 		t.Fatal(err)
 	}
-	if err := ioutil.WriteFile(filepath.Join(dir, "abc"), []byte("data for abc"), 0o666); err != nil {
+	if err := os.WriteFile(filepath.Join(dir, "abc"), []byte("data for abc"), 0o666); err != nil {
 		t.Fatal(err)
 	}
 	want := htop("h1", fmt.Sprintf("%s  %s\n%s  %s\n", h("data for abc"), "prefix/abc", h("data for xyz"), "prefix/xyz"))
@@ -69,7 +68,7 @@ func TestHashDir(t *testing.T) {
 }
 
 func TestHashZip(t *testing.T) {
-	f, err := ioutil.TempFile("", "dirhash-test-")
+	f, err := os.CreateTemp("", "dirhash-test-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -105,21 +104,21 @@ func TestHashZip(t *testing.T) {
 }
 
 func TestDirFiles(t *testing.T) {
-	dir, err := ioutil.TempDir("", "dirfiles-test-")
+	dir, err := os.MkdirTemp("", "dirfiles-test-")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(dir)
-	if err := ioutil.WriteFile(filepath.Join(dir, "xyz"), []byte("data for xyz"), 0o666); err != nil {
+	if err := os.WriteFile(filepath.Join(dir, "xyz"), []byte("data for xyz"), 0o666); err != nil {
 		t.Fatal(err)
 	}
-	if err := ioutil.WriteFile(filepath.Join(dir, "abc"), []byte("data for abc"), 0o666); err != nil {
+	if err := os.WriteFile(filepath.Join(dir, "abc"), []byte("data for abc"), 0o666); err != nil {
 		t.Fatal(err)
 	}
 	if err := os.Mkdir(filepath.Join(dir, "subdir"), 0o777); err != nil {
 		t.Fatal(err)
 	}
-	if err := ioutil.WriteFile(filepath.Join(dir, "subdir", "xyz"), []byte("data for subdir xyz"), 0o666); err != nil {
+	if err := os.WriteFile(filepath.Join(dir, "subdir", "xyz"), []byte("data for subdir xyz"), 0o666); err != nil {
 		t.Fatal(err)
 	}
 	prefix := "foo/bar@v2.3.4"
diff --git a/imports/scan.go b/imports/scan.go
index d944e957..e69e271e 100644
--- a/imports/scan.go
+++ b/imports/scan.go
@@ -6,7 +6,6 @@ package imports
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -15,14 +14,14 @@ import (
 )
 
 func ScanDir(dir string, tags map[string]bool) ([]string, []string, error) {
-	infos, err := ioutil.ReadDir(dir)
+	infos, err := os.ReadDir(dir)
 	if err != nil {
 		return nil, nil, err
 	}
 	var files []string
 	for _, info := range infos {
 		name := info.Name()
-		if info.Mode().IsRegular() && !strings.HasPrefix(name, "_") && strings.HasSuffix(name, ".go") && MatchFile(name, tags) {
+		if info.Type().IsRegular() && !strings.HasPrefix(name, "_") && strings.HasSuffix(name, ".go") && MatchFile(name, tags) {
 			files = append(files, filepath.Join(dir, name))
 		}
 	}
diff --git a/renameio/renameio.go b/renameio/renameio.go
index 234ec555..c05cecf0 100644
--- a/renameio/renameio.go
+++ b/renameio/renameio.go
@@ -10,7 +10,6 @@ package renameio
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 )
@@ -35,7 +34,7 @@ func WriteFile(filename string, data []byte) (err error) {
 // WriteToFile is a variant of WriteFile that accepts the data as an io.Reader
 // instead of a slice.
 func WriteToFile(filename string, data io.Reader) (err error) {
-	f, err := ioutil.TempFile(filepath.Dir(filename), filepath.Base(filename)+patternSuffix)
+	f, err := os.CreateTemp(filepath.Dir(filename), filepath.Base(filename)+patternSuffix)
 	if err != nil {
 		return err
 	}
diff --git a/testenv/testenv_windows.go b/testenv/testenv_windows.go
index eb8d6ac1..4802b139 100644
--- a/testenv/testenv_windows.go
+++ b/testenv/testenv_windows.go
@@ -5,7 +5,6 @@
 package testenv
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sync"
@@ -16,7 +15,7 @@ var symlinkOnce sync.Once
 var winSymlinkErr error
 
 func initWinHasSymlink() {
-	tmpdir, err := ioutil.TempDir("", "symtest")
+	tmpdir, err := os.MkdirTemp("", "symtest")
 	if err != nil {
 		panic("failed to create temp directory: " + err.Error())
 	}
diff --git a/testscript/cmd.go b/testscript/cmd.go
index dd8c1365..5e450766 100644
--- a/testscript/cmd.go
+++ b/testscript/cmd.go
@@ -8,7 +8,6 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -120,7 +119,7 @@ func (ts *TestScript) doCmdCmp(neg bool, args []string, env bool) {
 	text1 := ts.ReadFile(name1)
 
 	absName2 := ts.MkAbs(name2)
-	data, err := ioutil.ReadFile(absName2)
+	data, err := os.ReadFile(absName2)
 	ts.Check(err)
 	text2 := string(data)
 	if env {
@@ -191,14 +190,14 @@ func (ts *TestScript) cmdCp(neg bool, args []string) {
 			info, err := os.Stat(src)
 			ts.Check(err)
 			mode = info.Mode() & 0o777
-			data, err = ioutil.ReadFile(src)
+			data, err = os.ReadFile(src)
 			ts.Check(err)
 		}
 		targ := dst
 		if dstDir {
 			targ = filepath.Join(dst, filepath.Base(src))
 		}
-		ts.Check(ioutil.WriteFile(targ, data, mode))
+		ts.Check(os.WriteFile(targ, data, mode))
 	}
 }
 
@@ -337,11 +336,11 @@ func (ts *TestScript) cmdUnquote(neg bool, args []string) {
 	}
 	for _, arg := range args {
 		file := ts.MkAbs(arg)
-		data, err := ioutil.ReadFile(file)
+		data, err := os.ReadFile(file)
 		ts.Check(err)
 		data, err = txtar.Unquote(data)
 		ts.Check(err)
-		err = ioutil.WriteFile(file, data, 0o666)
+		err = os.WriteFile(file, data, 0o666)
 		ts.Check(err)
 	}
 }
@@ -482,11 +481,11 @@ func (ts *TestScript) cmdUNIX2DOS(neg bool, args []string) {
 	}
 	for _, arg := range args {
 		filename := ts.MkAbs(arg)
-		data, err := ioutil.ReadFile(filename)
+		data, err := os.ReadFile(filename)
 		ts.Check(err)
 		dosData, err := unix2DOS(data)
 		ts.Check(err)
-		if err := ioutil.WriteFile(filename, dosData, 0o666); err != nil {
+		if err := os.WriteFile(filename, dosData, 0o666); err != nil {
 			ts.Fatalf("%s: %v", filename, err)
 		}
 	}
@@ -632,7 +631,7 @@ func scriptMatch(ts *TestScript, neg bool, args []string, text, name string) {
 	isGrep := name == "grep"
 	if isGrep {
 		name = args[1] // for error messages
-		data, err := ioutil.ReadFile(ts.MkAbs(args[1]))
+		data, err := os.ReadFile(ts.MkAbs(args[1]))
 		ts.Check(err)
 		text = string(data)
 	}
diff --git a/testscript/exe.go b/testscript/exe.go
index 95e90b92..0ccd7738 100644
--- a/testscript/exe.go
+++ b/testscript/exe.go
@@ -6,7 +6,6 @@ package testscript
 
 import (
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
@@ -56,7 +55,7 @@ func RunMain(m TestingM, commands map[string]func() int) (exitCode int) {
 		// test binary by "go test".
 
 		// Set up all commands in a directory, added in $PATH.
-		tmpdir, err := ioutil.TempDir("", "testscript-main")
+		tmpdir, err := os.MkdirTemp("", "testscript-main")
 		if err != nil {
 			log.Printf("could not set up temporary directory: %v", err)
 			return 2
diff --git a/testscript/testscript_test.go b/testscript/testscript_test.go
index 2b4c6d32..4a62dbb7 100644
--- a/testscript/testscript_test.go
+++ b/testscript/testscript_test.go
@@ -9,7 +9,6 @@ import (
 	"errors"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"os/signal"
@@ -49,7 +48,7 @@ func signalCatcher() int {
 	signal.Notify(c, os.Interrupt)
 	// Create a file so that the test can know that
 	// we will catch the signal.
-	if err := ioutil.WriteFile("catchsignal", nil, 0o666); err != nil {
+	if err := os.WriteFile("catchsignal", nil, 0o666); err != nil {
 		fmt.Println(err)
 		return 1
 	}
@@ -90,16 +89,10 @@ func TestMain(m *testing.M) {
 }
 
 func TestCRLFInput(t *testing.T) {
-	td, err := ioutil.TempDir("", "")
-	if err != nil {
-		t.Fatalf("failed to create TempDir: %v", err)
-	}
-	defer func() {
-		os.RemoveAll(td)
-	}()
+	td := t.TempDir()
 	tf := filepath.Join(td, "script.txt")
 	contents := []byte("exists output.txt\r\n-- output.txt --\r\noutput contents")
-	if err := ioutil.WriteFile(tf, contents, 0o644); err != nil {
+	if err := os.WriteFile(tf, contents, 0o644); err != nil {
 		t.Fatalf("failed to write to %v: %v", tf, err)
 	}
 	t.Run("_", func(t *testing.T) {
@@ -272,7 +265,7 @@ func TestScripts(t *testing.T) {
 			"echoandexit": echoandexit,
 		},
 		Setup: func(env *Env) error {
-			infos, err := ioutil.ReadDir(env.WorkDir)
+			infos, err := os.ReadDir(env.WorkDir)
 			if err != nil {
 				return fmt.Errorf("cannot read workdir: %v", err)
 			}
@@ -350,11 +343,7 @@ func TestTestwork(t *testing.T) {
 
 // TestWorkdirRoot tests that a non zero value in Params.WorkdirRoot is honoured
 func TestWorkdirRoot(t *testing.T) {
-	td, err := ioutil.TempDir("", "")
-	if err != nil {
-		t.Fatalf("failed to create temp dir: %v", err)
-	}
-	defer os.RemoveAll(td)
+	td := t.TempDir()
 	params := Params{
 		Dir:         filepath.Join("testdata", "nothing"),
 		WorkdirRoot: td,
diff --git a/txtar/archive.go b/txtar/archive.go
index d14d4074..eaf5a1e9 100644
--- a/txtar/archive.go
+++ b/txtar/archive.go
@@ -35,7 +35,6 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -60,7 +59,7 @@ func Format(a *Archive) []byte {
 
 // ParseFile parses the named file as an archive.
 func ParseFile(file string) (*Archive, error) {
-	data, err := ioutil.ReadFile(file)
+	data, err := os.ReadFile(file)
 	if err != nil {
 		return nil, err
 	}
diff --git a/txtar/archive_test.go b/txtar/archive_test.go
index 7a74fd5b..519f8a7b 100644
--- a/txtar/archive_test.go
+++ b/txtar/archive_test.go
@@ -7,8 +7,6 @@ package txtar
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
-	"os"
 	"reflect"
 	"testing"
 )
@@ -81,11 +79,7 @@ func shortArchive(a *Archive) string {
 }
 
 func TestWrite(t *testing.T) {
-	td, err := ioutil.TempDir("", "")
-	if err != nil {
-		t.Fatalf("failed to create temp dir: %v", err)
-	}
-	defer os.RemoveAll(td)
+	td := t.TempDir()
 
 	good := &Archive{Files: []File{File{Name: "good.txt"}}}
 	if err := Write(good, td); err != nil {