diff --git a/execabs/execabs_test.go b/execabs/execabs_test.go
index 6e96fdf8..30d371ef 100644
--- a/execabs/execabs_test.go
+++ b/execabs/execabs_test.go
@@ -7,7 +7,6 @@ package execabs
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -63,8 +62,8 @@ func TestCommand(t *testing.T) {
 		if runtime.GOOS == "windows" {
 			executable += ".exe"
 		}
-		if err := ioutil.WriteFile(filepath.Join(tmpDir, executable), []byte{1, 2, 3}, 0111); err != nil {
-			t.Fatalf("ioutil.WriteFile failed: %s", err)
+		if err := os.WriteFile(filepath.Join(tmpDir, executable), []byte{1, 2, 3}, 0111); err != nil {
+			t.Fatal(err)
 		}
 		cwd, err := os.Getwd()
 		if err != nil {
@@ -98,8 +97,8 @@ func TestLookPath(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		executable += ".exe"
 	}
-	if err := ioutil.WriteFile(filepath.Join(tmpDir, executable), []byte{1, 2, 3}, 0111); err != nil {
-		t.Fatalf("ioutil.WriteFile failed: %s", err)
+	if err := os.WriteFile(filepath.Join(tmpDir, executable), []byte{1, 2, 3}, 0111); err != nil {
+		t.Fatal(err)
 	}
 	cwd, err := os.Getwd()
 	if err != nil {
diff --git a/unix/dirent_test.go b/unix/dirent_test.go
index e9dc3cb4..df6d422f 100644
--- a/unix/dirent_test.go
+++ b/unix/dirent_test.go
@@ -10,7 +10,7 @@ package unix_test
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"runtime"
 	"sort"
@@ -33,9 +33,9 @@ func TestDirent(t *testing.T) {
 
 	for i, c := range []byte("0123456789") {
 		name := string(bytes.Repeat([]byte{c}, filenameMinSize+i))
-		err := ioutil.WriteFile(filepath.Join(d, name), nil, 0644)
+		err := os.WriteFile(filepath.Join(d, name), nil, 0644)
 		if err != nil {
-			t.Fatalf("writefile: %v", err)
+			t.Fatal(err)
 		}
 	}
 
@@ -100,9 +100,9 @@ func TestDirentRepeat(t *testing.T) {
 		files = append(files, fmt.Sprintf("file%d", i))
 	}
 	for _, file := range files {
-		err := ioutil.WriteFile(filepath.Join(d, file), []byte("contents"), 0644)
+		err := os.WriteFile(filepath.Join(d, file), []byte("contents"), 0644)
 		if err != nil {
-			t.Fatalf("writefile: %v", err)
+			t.Fatal(err)
 		}
 	}
 
diff --git a/unix/getdirentries_test.go b/unix/getdirentries_test.go
index e73e8f95..023e6a14 100644
--- a/unix/getdirentries_test.go
+++ b/unix/getdirentries_test.go
@@ -9,7 +9,6 @@ package unix_test
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -39,9 +38,9 @@ func testGetdirentries(t *testing.T, count int) {
 
 	// Make files in the temp directory
 	for _, name := range names {
-		err := ioutil.WriteFile(filepath.Join(d, name), []byte("data"), 0)
+		err := os.WriteFile(filepath.Join(d, name), []byte("data"), 0)
 		if err != nil {
-			t.Fatalf("WriteFile: %v", err)
+			t.Fatal(err)
 		}
 	}
 
diff --git a/unix/mmap_zos_test.go b/unix/mmap_zos_test.go
index b9e6cd7a..513cc553 100644
--- a/unix/mmap_zos_test.go
+++ b/unix/mmap_zos_test.go
@@ -12,7 +12,6 @@ package unix_test
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
@@ -63,7 +62,7 @@ func TestMmap(t *testing.T) {
 	}
 
 	// Read file from FS to ensure flag flipped after msync
-	buf, err := ioutil.ReadFile(filename)
+	buf, err := os.ReadFile(filename)
 	if err != nil {
 		t.Fatalf("Could not read mmapped file from disc for test: %v", err)
 	}
diff --git a/unix/openbsd_test.go b/unix/openbsd_test.go
index 8da2cba8..4955943a 100644
--- a/unix/openbsd_test.go
+++ b/unix/openbsd_test.go
@@ -14,7 +14,6 @@ package unix_test
 import (
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -92,7 +91,7 @@ func init() {
 			os.Exit(0)
 		},
 		func() error {
-			files, err := ioutil.ReadDir(".")
+			files, err := os.ReadDir(".")
 			if err != nil {
 				return err
 			}
diff --git a/unix/sendfile_test.go b/unix/sendfile_test.go
index 0c028431..c4494e01 100644
--- a/unix/sendfile_test.go
+++ b/unix/sendfile_test.go
@@ -8,7 +8,7 @@
 package unix_test
 
 import (
-	"io/ioutil"
+	"io"
 	"net"
 	"os"
 	"path/filepath"
@@ -21,7 +21,7 @@ func TestSendfile(t *testing.T) {
 	// Set up source data file.
 	name := filepath.Join(t.TempDir(), "source")
 	const contents = "contents"
-	err := ioutil.WriteFile(name, []byte(contents), 0666)
+	err := os.WriteFile(name, []byte(contents), 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -41,7 +41,7 @@ func TestSendfile(t *testing.T) {
 			return
 		}
 		defer conn.Close()
-		b, err := ioutil.ReadAll(conn)
+		b, err := io.ReadAll(conn)
 		if err != nil {
 			t.Errorf("failed to read: %v", err)
 			return
diff --git a/unix/syscall_darwin_test.go b/unix/syscall_darwin_test.go
index 119f7df4..f17116a6 100644
--- a/unix/syscall_darwin_test.go
+++ b/unix/syscall_darwin_test.go
@@ -6,7 +6,6 @@ package unix_test
 
 import (
 	"bytes"
-	"io/ioutil"
 	"net"
 	"os"
 	"path/filepath"
@@ -51,7 +50,7 @@ func TestClonefile(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	clonedData, err := ioutil.ReadFile(clonedName)
+	clonedData, err := os.ReadFile(clonedName)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -72,7 +71,7 @@ func TestClonefileatWithCwd(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	clonedData, err := ioutil.ReadFile(clonedName)
+	clonedData, err := os.ReadFile(clonedName)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -116,7 +115,7 @@ func TestClonefileatWithRelativePaths(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	clonedData, err := ioutil.ReadFile(dstFile.Name())
+	clonedData, err := os.ReadFile(dstFile.Name())
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -149,7 +148,7 @@ func TestFclonefileat(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	clonedData, err := ioutil.ReadFile(dstFile.Name())
+	clonedData, err := os.ReadFile(dstFile.Name())
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/unix/syscall_linux_test.go b/unix/syscall_linux_test.go
index b0e3404b..ae2d6f43 100644
--- a/unix/syscall_linux_test.go
+++ b/unix/syscall_linux_test.go
@@ -12,7 +12,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"os"
 	"os/exec"
@@ -810,7 +810,7 @@ func TestOpenByHandleAt(t *testing.T) {
 			f := os.NewFile(uintptr(fd), "")
 			defer f.Close()
 
-			slurp, err := ioutil.ReadAll(f)
+			slurp, err := io.ReadAll(f)
 			if err != nil {
 				t.Fatal(err)
 			}
diff --git a/unix/syscall_unix_test.go b/unix/syscall_unix_test.go
index ac2092cb..10cddb43 100644
--- a/unix/syscall_unix_test.go
+++ b/unix/syscall_unix_test.go
@@ -11,7 +11,7 @@ import (
 	"bytes"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"os"
 	"os/exec"
@@ -260,7 +260,7 @@ func TestPassFD(t *testing.T) {
 	f := os.NewFile(uintptr(gotFds[0]), "fd-from-child")
 	defer f.Close()
 
-	got, err := ioutil.ReadAll(f)
+	got, err := io.ReadAll(f)
 	want := "Hello from child process!\n"
 	if string(got) != want {
 		t.Errorf("child process ReadAll: %q, %v; want %q", got, err, want)
diff --git a/unix/syscall_zos_test.go b/unix/syscall_zos_test.go
index fefe3f8a..30ace208 100644
--- a/unix/syscall_zos_test.go
+++ b/unix/syscall_zos_test.go
@@ -10,7 +10,7 @@ package unix_test
 import (
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"os"
 	"os/exec"
@@ -258,7 +258,7 @@ func TestPassFD(t *testing.T) {
 	f := os.NewFile(uintptr(gotFds[0]), "fd-from-child")
 	defer f.Close()
 
-	got, err := ioutil.ReadAll(f)
+	got, err := io.ReadAll(f)
 	want := "Hello from child process!\n"
 	if string(got) != want {
 		t.Errorf("child process ReadAll: %q, %v; want %q", got, err, want)
@@ -628,7 +628,7 @@ func TestChroot(t *testing.T) {
 		t.Fatalf("Chroot: %s", err.Error())
 	}
 	// check if tempDir contains test file
-	files, err := ioutil.ReadDir("/")
+	files, err := os.ReadDir("/")
 	if err != nil {
 		t.Fatalf("ReadDir: %s", err.Error())
 	}
diff --git a/windows/svc/svc_test.go b/windows/svc/svc_test.go
index 549cfeec..81161b85 100644
--- a/windows/svc/svc_test.go
+++ b/windows/svc/svc_test.go
@@ -9,7 +9,6 @@ package svc_test
 
 import (
 	"fmt"
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"os/exec"
@@ -202,7 +201,7 @@ func TestIsWindowsServiceWhenParentExits(t *testing.T) {
 		if isSvc {
 			msg = "IsWindowsService returns true when not running in a service."
 		}
-		err = ioutil.WriteFile(dumpPath, []byte(msg), 0644)
+		err = os.WriteFile(dumpPath, []byte(msg), 0644)
 		if err != nil {
 			// We cannot report this error. But main test will notice
 			// that we did not create dump file.
@@ -232,7 +231,7 @@ func TestIsWindowsServiceWhenParentExits(t *testing.T) {
 				t.Fatal("timed out waiting for child output file to be created.")
 			}
 		}
-		childOutput, err := ioutil.ReadFile(childDumpPath)
+		childOutput, err := os.ReadFile(childDumpPath)
 		if err != nil {
 			t.Fatalf("reading child output failed: %v", err)
 		}
diff --git a/windows/syscall_windows_test.go b/windows/syscall_windows_test.go
index 40b4d54e..f8996492 100644
--- a/windows/syscall_windows_test.go
+++ b/windows/syscall_windows_test.go
@@ -10,7 +10,6 @@ import (
 	"debug/pe"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"path/filepath"
@@ -667,14 +666,14 @@ func TestWinVerifyTrust(t *testing.T) {
 	// Now that we've verified the legitimate file verifies, let's corrupt it and see if it correctly fails.
 
 	corruptedEvsignedfile := filepath.Join(t.TempDir(), "corrupted-file")
-	evsignedfileBytes, err := ioutil.ReadFile(evsignedfile)
+	evsignedfileBytes, err := os.ReadFile(evsignedfile)
 	if err != nil {
 		t.Fatalf("unable to read %s bytes: %v", evsignedfile, err)
 	}
 	if len(evsignedfileBytes) > 0 {
 		evsignedfileBytes[len(evsignedfileBytes)/2-1]++
 	}
-	err = ioutil.WriteFile(corruptedEvsignedfile, evsignedfileBytes, 0755)
+	err = os.WriteFile(corruptedEvsignedfile, evsignedfileBytes, 0755)
 	if err != nil {
 		t.Fatalf("unable to write corrupted ntoskrnl.exe bytes: %v", err)
 	}