diff --git a/pkg/cmd/template/regular_input_test.go b/pkg/cmd/template/regular_input_test.go
index b94e3f13..71da5a05 100644
--- a/pkg/cmd/template/regular_input_test.go
+++ b/pkg/cmd/template/regular_input_test.go
@@ -7,7 +7,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"testing"
 
@@ -66,7 +66,7 @@ organization=Acme Widgets Inc.`)
 		files.MustNewFileFromSource(files.NewBytesSource("foo.yaml", yamlData)),
 	}
 
-	outputDir, err := ioutil.TempDir(os.TempDir(), "fakedir")
+	outputDir, err := os.MkdirTemp(os.TempDir(), "fakedir")
 	require.NoError(t, err)
 	defer os.RemoveAll(outputDir)
 
@@ -252,12 +252,12 @@ func TestFileMarkMultipleExcludes(t *testing.T) {
 }
 
 func assertStdoutAndStderr(t *testing.T, stdout *bytes.Buffer, stderr *bytes.Buffer, expectedStdOut string, expectedStdErr string) {
-	stdoutOutput, err := ioutil.ReadAll(stdout)
+	stdoutOutput, err := io.ReadAll(stdout)
 	require.NoError(t, err, "reading stdout")
 
 	require.Equal(t, expectedStdOut, string(stdoutOutput), "comparing stdout")
 
-	stderrOutput, err := ioutil.ReadAll(stderr)
+	stderrOutput, err := io.ReadAll(stderr)
 	require.NoError(t, err, "reading stdout")
 
 	require.Equal(t, expectedStdErr, string(stderrOutput), "comparing stderr")
diff --git a/pkg/files/sources.go b/pkg/files/sources.go
index 7119309c..7a59a6a9 100644
--- a/pkg/files/sources.go
+++ b/pkg/files/sources.go
@@ -5,7 +5,7 @@ package files
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"os"
 	"path"
@@ -81,7 +81,8 @@ func (s LocalSource) RelativePath() (string, error) {
 	return "", fmt.Errorf("unknown relative path for %s", s.path)
 }
 
-func (s LocalSource) Bytes() ([]byte, error) { return ioutil.ReadFile(s.path) }
+// Bytes returns  bytes of the read file
+func (s LocalSource) Bytes() ([]byte, error) { return os.ReadFile(s.path) }
 
 type HTTPSource struct {
 	url    string
@@ -109,7 +110,7 @@ func (s HTTPSource) Bytes() ([]byte, error) {
 		return nil, fmt.Errorf("Requesting URL '%s': %s", s.url, resp.Status)
 	}
 
-	result, err := ioutil.ReadAll(resp.Body)
+	result, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return nil, fmt.Errorf("Reading URL '%s': %s", s.url, err)
 	}
diff --git a/pkg/files/sources_test.go b/pkg/files/sources_test.go
index 09a0e5d0..0562abef 100644
--- a/pkg/files/sources_test.go
+++ b/pkg/files/sources_test.go
@@ -6,7 +6,7 @@ package files_test
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"testing"
 
@@ -23,7 +23,7 @@ func TestHTTPFileSources(t *testing.T) {
 		return &http.Response{
 			StatusCode: http.StatusOK,
 			// Send response to be tested
-			Body: ioutil.NopCloser(bytes.NewBufferString(`OK`)),
+			Body: io.NopCloser(bytes.NewBufferString(`OK`)),
 			// Must be set to non-nil value or it panics
 			Header: make(http.Header),
 		}
@@ -41,7 +41,7 @@ func TestHTTPFileSources(t *testing.T) {
 		require.Equal(t, req.URL.String(), url)
 		return &http.Response{
 			StatusCode: http.StatusIMUsed,
-			Body:       ioutil.NopCloser(bytes.NewBufferString(`OK`)),
+			Body:       io.NopCloser(bytes.NewBufferString(`OK`)),
 			Header:     make(http.Header),
 		}
 	})
diff --git a/pkg/files/stdin.go b/pkg/files/stdin.go
index ad1bd0e6..f7f6c4d7 100644
--- a/pkg/files/stdin.go
+++ b/pkg/files/stdin.go
@@ -5,7 +5,7 @@ package files
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 )
 
@@ -17,5 +17,5 @@ func ReadStdin() ([]byte, error) {
 		return nil, fmt.Errorf("Standard input has already been read, has the '-' argument been used in more than one flag?")
 	}
 	hasStdinBeenRead = true
-	return ioutil.ReadAll(os.Stdin)
+	return io.ReadAll(os.Stdin)
 }
diff --git a/pkg/texttemplate/template_test.go b/pkg/texttemplate/template_test.go
index 71f0c51e..a615fd94 100644
--- a/pkg/texttemplate/template_test.go
+++ b/pkg/texttemplate/template_test.go
@@ -5,7 +5,6 @@ package texttemplate_test
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -24,7 +23,7 @@ var (
 )
 
 func TestTextTemplate(t *testing.T) {
-	files, err := ioutil.ReadDir("filetests")
+	files, err := os.ReadDir("filetests")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -45,7 +44,7 @@ func TestTextTemplate(t *testing.T) {
 		testDesc := fmt.Sprintf("checking %s ...\n", file.Name())
 		fmt.Printf("%s", testDesc)
 
-		contents, err := ioutil.ReadFile(filePath)
+		contents, err := os.ReadFile(filePath)
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/pkg/website/server.go b/pkg/website/server.go
index b5763019..bdd146a3 100644
--- a/pkg/website/server.go
+++ b/pkg/website/server.go
@@ -6,7 +6,7 @@ package website
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net"
 	"net/http"
@@ -115,7 +115,7 @@ func (s *Server) examplesHandler(w http.ResponseWriter, r *http.Request) {
 }
 
 func (s *Server) templateHandler(w http.ResponseWriter, r *http.Request) {
-	data, err := ioutil.ReadAll(r.Body)
+	data, err := io.ReadAll(r.Body)
 	if err != nil {
 		s.logError(w, err)
 		return
diff --git a/pkg/yamlfmt/printer_test.go b/pkg/yamlfmt/printer_test.go
index 7b3db1fa..143049ed 100644
--- a/pkg/yamlfmt/printer_test.go
+++ b/pkg/yamlfmt/printer_test.go
@@ -5,7 +5,6 @@ package yamlfmt_test
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -51,7 +50,7 @@ func TestYAMLFmt(t *testing.T) {
 		testDesc := fmt.Sprintf("checking %s ...\n", filePath)
 		fmt.Printf("%s", testDesc)
 
-		contents, err := ioutil.ReadFile(filePath)
+		contents, err := os.ReadFile(filePath)
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/test/e2e/e2e_test.go b/test/e2e/e2e_test.go
index 42078fb6..c79cf048 100644
--- a/test/e2e/e2e_test.go
+++ b/test/e2e/e2e_test.go
@@ -7,7 +7,6 @@ import (
 	"bytes"
 	"fmt"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -111,7 +110,7 @@ float: 123.123
 			}
 			actualOutput := runYtt(t, testInputFiles{testDir + "/config"}, "", flags, nil)
 
-			expectedOutput, err := ioutil.ReadFile(filepath.Join(testDir, "expected.txt"))
+			expectedOutput, err := os.ReadFile(filepath.Join(testDir, "expected.txt"))
 			require.NoError(t, err)
 
 			require.Equal(t, string(expectedOutput), actualOutput)
@@ -138,7 +137,7 @@ float: 0
 
 	})
 	t.Run("can be 'required'", func(t *testing.T) {
-		expectedFileOutput, err := ioutil.ReadFile("../../examples/data-values-required/expected.txt")
+		expectedFileOutput, err := os.ReadFile("../../examples/data-values-required/expected.txt")
 		require.NoError(t, err)
 
 		dirs := []string{
@@ -212,7 +211,7 @@ func TestSchema(t *testing.T) {
 			dirPath := fmt.Sprintf("../../examples/%s", dir)
 			actualOutput := runYtt(t, testInputFiles{dirPath}, "", nil, nil)
 
-			expectedOutput, err := ioutil.ReadFile(filepath.Join(dirPath, "expected.txt"))
+			expectedOutput, err := os.ReadFile(filepath.Join(dirPath, "expected.txt"))
 			require.NoError(t, err)
 
 			require.Equal(t, string(expectedOutput), actualOutput)
@@ -232,7 +231,7 @@ func TestOverlays(t *testing.T) {
 			dirPath := fmt.Sprintf("../../examples/%s", dir)
 			actualOutput := runYtt(t, testInputFiles{dirPath}, "", nil, nil)
 
-			expectedOutput, err := ioutil.ReadFile(filepath.Join(dirPath, "expected.txt"))
+			expectedOutput, err := os.ReadFile(filepath.Join(dirPath, "expected.txt"))
 			require.NoError(t, err)
 
 			require.Equal(t, string(expectedOutput), actualOutput)
@@ -264,7 +263,7 @@ func TestReadingFromStandardIn(t *testing.T) {
 	t.Run("through --file", func(t *testing.T) {
 		actualOutput := runYtt(t, []string{"-", "../../examples/eirini/input.yml"}, "../../examples/eirini/config.yml", nil, nil)
 
-		expectedFileOutput, err := ioutil.ReadFile("../../examples/eirini/config-result.yml")
+		expectedFileOutput, err := os.ReadFile("../../examples/eirini/config-result.yml")
 		require.NoError(t, err)
 		require.Equal(t, string(expectedFileOutput), actualOutput)
 	})
@@ -294,16 +293,16 @@ new_thing: new
 }
 
 func TestCheckDirectoryOutput(t *testing.T) {
-	tempOutputDir, err := ioutil.TempDir(os.TempDir(), "ytt-check-dir")
+	tempOutputDir, err := os.MkdirTemp(os.TempDir(), "ytt-check-dir")
 	require.NoError(t, err)
 	defer os.Remove(tempOutputDir)
 	flags := yttFlags{{fmt.Sprintf("--dangerous-emptied-output-directory=%s", tempOutputDir): ""}}
 	runYtt(t, []string{"../../examples/eirini/"}, "", flags, nil)
 
-	expectedFileOutput, err := ioutil.ReadFile("../../examples/eirini/config-result.yml")
+	expectedFileOutput, err := os.ReadFile("../../examples/eirini/config-result.yml")
 	require.NoError(t, err)
 
-	actualOutput, err := ioutil.ReadFile(filepath.Join(tempOutputDir, "config-result.yml"))
+	actualOutput, err := os.ReadFile(filepath.Join(tempOutputDir, "config-result.yml"))
 	require.NoError(t, err)
 
 	require.Equal(t, string(expectedFileOutput), string(actualOutput))
@@ -371,7 +370,7 @@ func TestApplicationSpecificScenarios(t *testing.T) {
 				dirPath := fmt.Sprintf("../../examples/%s", dir)
 				actualOutput := runYtt(t, testInputFiles{dirPath}, "", nil, nil)
 
-				expectedOutput, err := ioutil.ReadFile(filepath.Join(dirPath, "expected.txt"))
+				expectedOutput, err := os.ReadFile(filepath.Join(dirPath, "expected.txt"))
 				require.NoError(t, err)
 
 				require.Equal(t, string(expectedOutput), actualOutput)
@@ -385,7 +384,7 @@ func TestApplicationSpecificScenarios(t *testing.T) {
 				dirPath := fmt.Sprintf("../../examples/%s", dir)
 				actualOutput := runYtt(t, testInputFiles{dirPath}, "", nil, nil)
 
-				expectedOutput, err := ioutil.ReadFile(filepath.Join(dirPath, "expected.txt"))
+				expectedOutput, err := os.ReadFile(filepath.Join(dirPath, "expected.txt"))
 				require.NoError(t, err)
 
 				require.Equal(t, string(expectedOutput), actualOutput)
@@ -396,14 +395,14 @@ func TestApplicationSpecificScenarios(t *testing.T) {
 		t.Run("config.yml", func(t *testing.T) {
 			actualOutput := runYtt(t, []string{"../../examples/eirini/config.yml", "../../examples/eirini/input.yml"}, "", nil, nil)
 
-			expectedFileOutput, err := ioutil.ReadFile("../../examples/eirini/config-result.yml")
+			expectedFileOutput, err := os.ReadFile("../../examples/eirini/config-result.yml")
 			require.NoError(t, err)
 			require.Equal(t, string(expectedFileOutput), actualOutput)
 		})
 		t.Run("config-alt1.yml", func(t *testing.T) {
 			actualOutput := runYtt(t, []string{"../../examples/eirini/config-alt1.yml", "../../examples/eirini/input.yml"}, "", nil, nil)
 
-			expectedFileOutput, err := ioutil.ReadFile("../../examples/eirini/config-result.yml")
+			expectedFileOutput, err := os.ReadFile("../../examples/eirini/config-result.yml")
 			require.NoError(t, err)
 			require.Equal(t, string(expectedFileOutput), actualOutput)
 		})
@@ -416,7 +415,7 @@ func TestApplicationSpecificScenarios(t *testing.T) {
 				"../../examples/eirini/input.yml"},
 				"", nil, nil)
 
-			expectedFileOutput, err := ioutil.ReadFile("../../examples/eirini/config-result.yml")
+			expectedFileOutput, err := os.ReadFile("../../examples/eirini/config-result.yml")
 			require.NoError(t, err)
 			require.Equal(t, string(expectedFileOutput), actualOutput)
 		})
@@ -434,7 +433,7 @@ func TestRemainingExamples(t *testing.T) {
 			dirPath := fmt.Sprintf("../../examples/%s", dir)
 			actualOutput := runYtt(t, testInputFiles{dirPath}, "", nil, nil)
 
-			expectedOutput, err := ioutil.ReadFile(filepath.Join(dirPath, "expected.txt"))
+			expectedOutput, err := os.ReadFile(filepath.Join(dirPath, "expected.txt"))
 			require.NoError(t, err)
 
 			require.Equal(t, string(expectedOutput), actualOutput)
diff --git a/test/filetests/filetests.go b/test/filetests/filetests.go
index 9378d78c..6a2a8dca 100644
--- a/test/filetests/filetests.go
+++ b/test/filetests/filetests.go
@@ -10,7 +10,6 @@ package filetests
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -86,7 +85,7 @@ func (f FileTests) Run(t *testing.T) {
 
 	for _, filePath := range files {
 		t.Run(filePath, func(t *testing.T) {
-			contents, err := ioutil.ReadFile(filePath)
+			contents, err := os.ReadFile(filePath)
 			if err != nil {
 				t.Fatal(err)
 			}