diff --git a/addrmgr/addrmanager_internal_test.go b/addrmgr/addrmanager_internal_test.go
index 1d13f78e6e..b39eff43ad 100644
--- a/addrmgr/addrmanager_internal_test.go
+++ b/addrmgr/addrmanager_internal_test.go
@@ -1,7 +1,6 @@
 package addrmgr
 
 import (
-	"io/ioutil"
 	"math/rand"
 	"net"
 	"os"
@@ -91,7 +90,7 @@ func TestAddrManagerSerialization(t *testing.T) {
 
 	// We'll start by creating our address manager backed by a temporary
 	// directory.
-	tempDir, err := ioutil.TempDir("", "addrmgr")
+	tempDir, err := os.MkdirTemp("", "addrmgr")
 	if err != nil {
 		t.Fatalf("unable to create temp dir: %v", err)
 	}
@@ -131,7 +130,7 @@ func TestAddrManagerV1ToV2(t *testing.T) {
 
 	// We'll start by creating our address manager backed by a temporary
 	// directory.
-	tempDir, err := ioutil.TempDir("", "addrmgr")
+	tempDir, err := os.MkdirTemp("", "addrmgr")
 	if err != nil {
 		t.Fatalf("unable to create temp dir: %v", err)
 	}
diff --git a/btcutil/txsort/txsort_test.go b/btcutil/txsort/txsort_test.go
index dd2149294e..16a3e61c83 100644
--- a/btcutil/txsort/txsort_test.go
+++ b/btcutil/txsort/txsort_test.go
@@ -7,7 +7,7 @@ package txsort_test
 import (
 	"bytes"
 	"encoding/hex"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"testing"
 
@@ -64,7 +64,7 @@ func TestSort(t *testing.T) {
 	for _, test := range tests {
 		// Load and deserialize the test transaction.
 		filePath := filepath.Join("testdata", test.hexFile)
-		txHexBytes, err := ioutil.ReadFile(filePath)
+		txHexBytes, err := os.ReadFile(filePath)
 		if err != nil {
 			t.Errorf("ReadFile (%s): failed to read test file: %v",
 				test.name, err)
diff --git a/cmd/btcctl/httpclient.go b/cmd/btcctl/httpclient.go
index 2a0f6dffd4..c7b4b7e3a1 100644
--- a/cmd/btcctl/httpclient.go
+++ b/cmd/btcctl/httpclient.go
@@ -6,9 +6,10 @@ import (
 	"crypto/x509"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"net/http"
+	"os"
 
 	"github.com/btcsuite/btcd/btcjson"
 	"github.com/btcsuite/go-socks/socks"
@@ -37,7 +38,7 @@ func newHTTPClient(cfg *config) (*http.Client, error) {
 	// Configure TLS if needed.
 	var tlsConfig *tls.Config
 	if !cfg.NoTLS && cfg.RPCCert != "" {
-		pem, err := ioutil.ReadFile(cfg.RPCCert)
+		pem, err := os.ReadFile(cfg.RPCCert)
 		if err != nil {
 			return nil, err
 		}
@@ -95,7 +96,7 @@ func sendPostRequest(marshalledJSON []byte, cfg *config) ([]byte, error) {
 	}
 
 	// Read the raw bytes and close the response.
-	respBytes, err := ioutil.ReadAll(httpResponse.Body)
+	respBytes, err := io.ReadAll(httpResponse.Body)
 	httpResponse.Body.Close()
 	if err != nil {
 		err = fmt.Errorf("error reading json reply: %v", err)
diff --git a/cmd/gencerts/gencerts.go b/cmd/gencerts/gencerts.go
index 27c9ae385c..328d5ea714 100644
--- a/cmd/gencerts/gencerts.go
+++ b/cmd/gencerts/gencerts.go
@@ -6,7 +6,6 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -65,11 +64,11 @@ func main() {
 	}
 
 	// Write cert and key files.
-	if err = ioutil.WriteFile(certFile, cert, 0666); err != nil {
+	if err = os.WriteFile(certFile, cert, 0666); err != nil {
 		fmt.Fprintf(os.Stderr, "cannot write cert: %v\n", err)
 		os.Exit(1)
 	}
-	if err = ioutil.WriteFile(keyFile, key, 0600); err != nil {
+	if err = os.WriteFile(keyFile, key, 0600); err != nil {
 		os.Remove(certFile)
 		fmt.Fprintf(os.Stderr, "cannot write key: %v\n", err)
 		os.Exit(1)
diff --git a/config_test.go b/config_test.go
index e54a9f5f20..42a0cd4b90 100644
--- a/config_test.go
+++ b/config_test.go
@@ -1,7 +1,6 @@
 package main
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -23,14 +22,14 @@ func TestCreateDefaultConfigFile(t *testing.T) {
 	sampleConfigFile := filepath.Join(filepath.Dir(path), "sample-btcd.conf")
 
 	// Setup a temporary directory
-	tmpDir, err := ioutil.TempDir("", "btcd")
+	tmpDir, err := os.MkdirTemp("", "btcd")
 	if err != nil {
 		t.Fatalf("Failed creating a temporary directory: %v", err)
 	}
 	testpath := filepath.Join(tmpDir, "test.conf")
 
 	// copy config file to location of btcd binary
-	data, err := ioutil.ReadFile(sampleConfigFile)
+	data, err := os.ReadFile(sampleConfigFile)
 	if err != nil {
 		t.Fatalf("Failed reading sample config file: %v", err)
 	}
@@ -39,7 +38,7 @@ func TestCreateDefaultConfigFile(t *testing.T) {
 		t.Fatalf("Failed obtaining app path: %v", err)
 	}
 	tmpConfigFile := filepath.Join(appPath, "sample-btcd.conf")
-	err = ioutil.WriteFile(tmpConfigFile, data, 0644)
+	err = os.WriteFile(tmpConfigFile, data, 0644)
 	if err != nil {
 		t.Fatalf("Failed copying sample config file: %v", err)
 	}
@@ -57,7 +56,7 @@ func TestCreateDefaultConfigFile(t *testing.T) {
 		t.Fatalf("Failed to create a default config file: %v", err)
 	}
 
-	content, err := ioutil.ReadFile(testpath)
+	content, err := os.ReadFile(testpath)
 	if err != nil {
 		t.Fatalf("Failed to read generated default config file: %v", err)
 	}
diff --git a/database/example_test.go b/database/example_test.go
index b64baf2c8e..1110d0dbc3 100644
--- a/database/example_test.go
+++ b/database/example_test.go
@@ -7,7 +7,6 @@ package database_test
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -123,7 +122,7 @@ func Example_blockStorageAndRetrieval() {
 	// Typically you wouldn't want to remove the database right away like
 	// this, nor put it in the temp directory, but it's done here to ensure
 	// the example cleans up after itself.
-	dbPath, err := ioutil.TempDir("", "exampleblkstorage")
+	dbPath, err := os.MkdirTemp("", "exampleblkstorage")
 	if err != nil {
 		fmt.Println(err)
 		return
diff --git a/docs/json_rpc_api.md b/docs/json_rpc_api.md
index 2c7d455457..fc32040da7 100644
--- a/docs/json_rpc_api.md
+++ b/docs/json_rpc_api.md
@@ -1121,7 +1121,7 @@ func main() {
 	// generated by btcd when it starts the RPC server and doesn't already
 	// have one.
 	btcdHomeDir := btcutil.AppDataDir("btcd", false)
-	certs, err := ioutil.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
+	certs, err := os.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -1185,7 +1185,7 @@ func main() {
 	// generated by btcd when it starts the RPC server and doesn't already
 	// have one.
 	btcdHomeDir := btcutil.AppDataDir("btcd", false)
-	certs, err := ioutil.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
+	certs, err := os.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -1288,7 +1288,7 @@ func main() {
 	// generated by btcd when it starts the RPC server and doesn't already
 	// have one.
 	btcdHomeDir := btcutil.AppDataDir("btcd", false)
-	certs, err := ioutil.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
+	certs, err := os.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/rpcclient/examples/btcdwebsockets/main.go b/rpcclient/examples/btcdwebsockets/main.go
index e3f4c13e40..878526b076 100644
--- a/rpcclient/examples/btcdwebsockets/main.go
+++ b/rpcclient/examples/btcdwebsockets/main.go
@@ -5,7 +5,7 @@
 package main
 
 import (
-	"io/ioutil"
+	"os"
 	"log"
 	"path/filepath"
 	"time"
@@ -33,7 +33,7 @@ func main() {
 
 	// Connect to local btcd RPC server using websockets.
 	btcdHomeDir := btcutil.AppDataDir("btcd", false)
-	certs, err := ioutil.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
+	certs, err := os.ReadFile(filepath.Join(btcdHomeDir, "rpc.cert"))
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/rpcclient/examples/btcwalletwebsockets/main.go b/rpcclient/examples/btcwalletwebsockets/main.go
index 3cbd9a3667..a63ef3db91 100644
--- a/rpcclient/examples/btcwalletwebsockets/main.go
+++ b/rpcclient/examples/btcwalletwebsockets/main.go
@@ -5,7 +5,7 @@
 package main
 
 import (
-	"io/ioutil"
+	"os"
 	"log"
 	"path/filepath"
 	"time"
@@ -29,7 +29,7 @@ func main() {
 
 	// Connect to local btcwallet RPC server using websockets.
 	certHomeDir := btcutil.AppDataDir("btcwallet", false)
-	certs, err := ioutil.ReadFile(filepath.Join(certHomeDir, "rpc.cert"))
+	certs, err := os.ReadFile(filepath.Join(certHomeDir, "rpc.cert"))
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/rpcserver.go b/rpcserver.go
index d6f3167f1e..eaa5f05633 100644
--- a/rpcserver.go
+++ b/rpcserver.go
@@ -4650,10 +4650,10 @@ func genCertPair(certFile, keyFile string) error {
 	}
 
 	// Write cert and key files.
-	if err = ioutil.WriteFile(certFile, cert, 0666); err != nil {
+	if err = os.WriteFile(certFile, cert, 0666); err != nil {
 		return err
 	}
-	if err = ioutil.WriteFile(keyFile, key, 0600); err != nil {
+	if err = os.WriteFile(keyFile, key, 0600); err != nil {
 		os.Remove(certFile)
 		return err
 	}
diff --git a/txscript/bench_test.go b/txscript/bench_test.go
index 0d1aa91468..60b0d9e12e 100644
--- a/txscript/bench_test.go
+++ b/txscript/bench_test.go
@@ -7,7 +7,7 @@ package txscript
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"testing"
 
 	"github.com/btcsuite/btcd/chaincfg"
@@ -25,7 +25,7 @@ var (
 
 func init() {
 	// tx 620f57c92cf05a7f7e7f7d28255d5f7089437bc48e34dcfebf7751d08b7fb8f5
-	txHex, err := ioutil.ReadFile("data/many_inputs_tx.hex")
+	txHex, err := os.ReadFile("data/many_inputs_tx.hex")
 	if err != nil {
 		panic(fmt.Sprintf("unable to read benchmark tx file: %v", err))
 	}
diff --git a/txscript/reference_test.go b/txscript/reference_test.go
index 59acdb8da7..16f06c4f70 100644
--- a/txscript/reference_test.go
+++ b/txscript/reference_test.go
@@ -11,7 +11,7 @@ import (
 	"errors"
 	"fmt"
 	"io/fs"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -490,7 +490,7 @@ func testScripts(t *testing.T, tests [][]interface{}, useSigCache bool) {
 // TestScripts ensures all of the tests in script_tests.json execute with the
 // expected results as defined in the test data.
 func TestScripts(t *testing.T) {
-	file, err := ioutil.ReadFile("data/script_tests.json")
+	file, err := os.ReadFile("data/script_tests.json")
 	if err != nil {
 		t.Fatalf("TestScripts: %v\n", err)
 	}
@@ -521,7 +521,7 @@ func testVecF64ToUint32(f float64) uint32 {
 // TestTxInvalidTests ensures all of the tests in tx_invalid.json fail as
 // expected.
 func TestTxInvalidTests(t *testing.T) {
-	file, err := ioutil.ReadFile("data/tx_invalid.json")
+	file, err := os.ReadFile("data/tx_invalid.json")
 	if err != nil {
 		t.Fatalf("TestTxInvalidTests: %v\n", err)
 	}
@@ -679,7 +679,7 @@ testloop:
 
 // TestTxValidTests ensures all of the tests in tx_valid.json pass as expected.
 func TestTxValidTests(t *testing.T) {
-	file, err := ioutil.ReadFile("data/tx_valid.json")
+	file, err := os.ReadFile("data/tx_valid.json")
 	if err != nil {
 		t.Fatalf("TestTxValidTests: %v\n", err)
 	}
@@ -836,7 +836,7 @@ testloop:
 // in sighash.json.
 // https://github.com/bitcoin/bitcoin/blob/master/src/test/data/sighash.json
 func TestCalcSignatureHash(t *testing.T) {
-	file, err := ioutil.ReadFile("data/sighash.json")
+	file, err := os.ReadFile("data/sighash.json")
 	if err != nil {
 		t.Fatalf("TestCalcSignatureHash: %v\n", err)
 	}
@@ -1044,7 +1044,7 @@ func TestTaprootReferenceTests(t *testing.T) {
 			return nil
 		}
 
-		testJson, err := ioutil.ReadFile(path)
+		testJson, err := os.ReadFile(path)
 		if err != nil {
 			return fmt.Errorf("unable to read file: %v", err)
 		}