diff --git a/chat.go b/chat.go
index 916d05a93..18f8e933d 100644
--- a/chat.go
+++ b/chat.go
@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/url"
 	"regexp"
@@ -226,11 +226,11 @@ func (api *Client) SendMessageContext(ctx context.Context, channelID string, opt
 	}
 
 	if api.Debug() {
-		reqBody, err := ioutil.ReadAll(req.Body)
+		reqBody, err := io.ReadAll(req.Body)
 		if err != nil {
 			return "", "", "", err
 		}
-		req.Body = ioutil.NopCloser(bytes.NewBuffer(reqBody))
+		req.Body = io.NopCloser(bytes.NewBuffer(reqBody))
 		api.Debugf("Sending request: %s", redactToken(reqBody))
 	}
 
diff --git a/chat_test.go b/chat_test.go
index ee93bddff..917ff965e 100644
--- a/chat_test.go
+++ b/chat_test.go
@@ -3,7 +3,7 @@ package slack
 import (
 	"bytes"
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/url"
@@ -216,7 +216,7 @@ func TestPostMessage(t *testing.T) {
 		t.Run(name, func(t *testing.T) {
 			http.DefaultServeMux = new(http.ServeMux)
 			http.HandleFunc(test.endpoint, func(rw http.ResponseWriter, r *http.Request) {
-				body, err := ioutil.ReadAll(r.Body)
+				body, err := io.ReadAll(r.Body)
 				if err != nil {
 					t.Errorf("unexpected error: %v", err)
 					return
@@ -242,7 +242,7 @@ func TestPostMessageWithBlocksWhenMsgOptionResponseURLApplied(t *testing.T) {
 
 	http.DefaultServeMux = new(http.ServeMux)
 	http.HandleFunc("/response-url", func(rw http.ResponseWriter, r *http.Request) {
-		body, err := ioutil.ReadAll(r.Body)
+		body, err := io.ReadAll(r.Body)
 		if err != nil {
 			t.Errorf("unexpected error: %v", err)
 			return
@@ -270,7 +270,7 @@ func TestPostMessageWithBlocksWhenMsgOptionResponseURLApplied(t *testing.T) {
 func TestPostMessageWhenMsgOptionReplaceOriginalApplied(t *testing.T) {
 	http.DefaultServeMux = new(http.ServeMux)
 	http.HandleFunc("/response-url", func(rw http.ResponseWriter, r *http.Request) {
-		body, err := ioutil.ReadAll(r.Body)
+		body, err := io.ReadAll(r.Body)
 		if err != nil {
 			t.Errorf("unexpected error: %v", err)
 			return
@@ -297,7 +297,7 @@ func TestPostMessageWhenMsgOptionReplaceOriginalApplied(t *testing.T) {
 func TestPostMessageWhenMsgOptionDeleteOriginalApplied(t *testing.T) {
 	http.DefaultServeMux = new(http.ServeMux)
 	http.HandleFunc("/response-url", func(rw http.ResponseWriter, r *http.Request) {
-		body, err := ioutil.ReadAll(r.Body)
+		body, err := io.ReadAll(r.Body)
 		if err != nil {
 			t.Errorf("unexpected error: %v", err)
 			return
diff --git a/examples/dialog/dialog.go b/examples/dialog/dialog.go
index 4b4d6ab18..dc0d431c3 100644
--- a/examples/dialog/dialog.go
+++ b/examples/dialog/dialog.go
@@ -2,7 +2,7 @@ package main
 
 import (
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/url"
@@ -26,7 +26,7 @@ func handler(w http.ResponseWriter, r *http.Request) {
 
 	// Read request body
 	defer r.Body.Close()
-	body, err := ioutil.ReadAll(r.Body)
+	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		w.WriteHeader(http.StatusInternalServerError)
 		log.Printf("[ERROR] Fail to read request body: %v", err)
diff --git a/examples/eventsapi/events.go b/examples/eventsapi/events.go
index 25049ad07..b3bb70ab4 100644
--- a/examples/eventsapi/events.go
+++ b/examples/eventsapi/events.go
@@ -3,7 +3,7 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"os"
 
@@ -18,7 +18,7 @@ func main() {
 	signingSecret := os.Getenv("SLACK_SIGNING_SECRET")
 
 	http.HandleFunc("/events-endpoint", func(w http.ResponseWriter, r *http.Request) {
-		body, err := ioutil.ReadAll(r.Body)
+		body, err := io.ReadAll(r.Body)
 		if err != nil {
 			w.WriteHeader(http.StatusBadRequest)
 			return
diff --git a/examples/modal/modal.go b/examples/modal/modal.go
index 155f2f714..13115a826 100644
--- a/examples/modal/modal.go
+++ b/examples/modal/modal.go
@@ -15,7 +15,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 
 	"github.com/slack-go/slack"
@@ -95,13 +95,13 @@ func verifySigningSecret(r *http.Request) error {
 		return err
 	}
 
-	body, err := ioutil.ReadAll(r.Body)
+	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		fmt.Println(err.Error())
 		return err
 	}
 	// Need to use r.Body again when unmarshalling SlashCommand and InteractionCallback
-	r.Body = ioutil.NopCloser(bytes.NewBuffer(body))
+	r.Body = io.NopCloser(bytes.NewBuffer(body))
 
 	verifier.Write(body)
 	if err = verifier.Ensure(); err != nil {
diff --git a/examples/slash/slash.go b/examples/slash/slash.go
index c70c865ff..e35ab10a8 100644
--- a/examples/slash/slash.go
+++ b/examples/slash/slash.go
@@ -5,7 +5,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 
 	"github.com/slack-go/slack"
@@ -27,7 +26,7 @@ func main() {
 			return
 		}
 
-		r.Body = ioutil.NopCloser(io.TeeReader(r.Body, &verifier))
+		r.Body = io.NopCloser(io.TeeReader(r.Body, &verifier))
 		s, err := slack.SlashCommandParse(r)
 		if err != nil {
 			w.WriteHeader(http.StatusInternalServerError)
diff --git a/examples/workflow_step/handler.go b/examples/workflow_step/handler.go
index b25a5be42..d0eee101f 100644
--- a/examples/workflow_step/handler.go
+++ b/examples/workflow_step/handler.go
@@ -3,7 +3,7 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/url"
@@ -25,7 +25,7 @@ func handleMyWorkflowStep(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// see: https://github.com/slack-go/slack/blob/master/examples/eventsapi/events.go
-	body, err := ioutil.ReadAll(r.Body)
+	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
@@ -88,7 +88,7 @@ func handleInteraction(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	body, err := ioutil.ReadAll(r.Body)
+	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
diff --git a/examples/workflow_step/middleware.go b/examples/workflow_step/middleware.go
index 0684e50d6..6fe826910 100644
--- a/examples/workflow_step/middleware.go
+++ b/examples/workflow_step/middleware.go
@@ -2,20 +2,20 @@ package main
 
 import (
 	"bytes"
-	"io/ioutil"
+	"io"
 	"net/http"
 
 	"github.com/slack-go/slack"
 )
 
 func (v *SecretsVerifierMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	body, err := ioutil.ReadAll(r.Body)
+	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 	r.Body.Close()
-	r.Body = ioutil.NopCloser(bytes.NewBuffer(body))
+	r.Body = io.NopCloser(bytes.NewBuffer(body))
 
 	sv, err := slack.NewSecretsVerifier(r.Header, appCtx.config.signingSecret)
 	if err != nil {
diff --git a/files_test.go b/files_test.go
index 59afc1c4b..1df46aa6e 100644
--- a/files_test.go
+++ b/files_test.go
@@ -3,7 +3,7 @@ package slack
 import (
 	"bytes"
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/url"
@@ -44,7 +44,7 @@ func (h *fileCommentHandler) handler(w http.ResponseWriter, r *http.Request) {
 type mockHTTPClient struct{}
 
 func (m *mockHTTPClient) Do(*http.Request) (*http.Response, error) {
-	return &http.Response{StatusCode: 200, Body: ioutil.NopCloser(bytes.NewBufferString(`OK`))}, nil
+	return &http.Response{StatusCode: 200, Body: io.NopCloser(bytes.NewBufferString(`OK`))}, nil
 }
 
 func TestSlack_GetFile(t *testing.T) {
diff --git a/misc.go b/misc.go
index 7e5a8d54a..a25afb65e 100644
--- a/misc.go
+++ b/misc.go
@@ -7,7 +7,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"mime"
 	"mime/multipart"
 	"net/http"
@@ -127,7 +126,7 @@ func jsonReq(ctx context.Context, endpoint string, body interface{}) (req *http.
 }
 
 func parseResponseBody(body io.ReadCloser, intf interface{}, d Debug) error {
-	response, err := ioutil.ReadAll(body)
+	response, err := io.ReadAll(body)
 	if err != nil {
 		return err
 	}
@@ -316,7 +315,7 @@ func newJSONParser(dst interface{}) responseParser {
 
 func newTextParser(dst interface{}) responseParser {
 	return func(resp *http.Response) error {
-		b, err := ioutil.ReadAll(resp.Body)
+		b, err := io.ReadAll(resp.Body)
 		if err != nil {
 			return err
 		}
diff --git a/reminders_test.go b/reminders_test.go
index 25291b543..09dd6a096 100644
--- a/reminders_test.go
+++ b/reminders_test.go
@@ -2,7 +2,7 @@ package slack
 
 import (
 	"bytes"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"reflect"
 	"testing"
@@ -185,7 +185,7 @@ func (m *mockRemindersListHTTPClient) Do(*http.Request) (*http.Response, error)
 		]
 	}`
 
-	return &http.Response{StatusCode: 200, Body: ioutil.NopCloser(bytes.NewBufferString(responseString))}, nil
+	return &http.Response{StatusCode: 200, Body: io.NopCloser(bytes.NewBufferString(responseString))}, nil
 }
 
 func TestSlack_ListReminders(t *testing.T) {
diff --git a/slacktest/handlers.go b/slacktest/handlers.go
index b4a0227f3..22c1680f6 100644
--- a/slacktest/handlers.go
+++ b/slacktest/handlers.go
@@ -4,7 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/url"
@@ -46,7 +46,7 @@ type GroupConversationResponse struct {
 }
 
 func (sts *Server) conversationsInfoHandler(w http.ResponseWriter, r *http.Request) {
-	data, err := ioutil.ReadAll(r.Body)
+	data, err := io.ReadAll(r.Body)
 	if err != nil {
 		msg := fmt.Sprintf("error reading body: %s", err.Error())
 		log.Printf(msg)
@@ -126,7 +126,7 @@ func reactionAddHandler(w http.ResponseWriter, _ *http.Request) {
 // handle chat.postMessage
 func (sts *Server) postMessageHandler(w http.ResponseWriter, r *http.Request) {
 	serverAddr := r.Context().Value(ServerBotHubNameContextKey).(string)
-	data, err := ioutil.ReadAll(r.Body)
+	data, err := io.ReadAll(r.Body)
 	if err != nil {
 		msg := fmt.Sprintf("error reading body: %s", err.Error())
 		log.Printf(msg)
@@ -218,7 +218,7 @@ func (sts *Server) postMessageHandler(w http.ResponseWriter, r *http.Request) {
 
 // RTMConnectHandler generates a valid connection
 func RTMConnectHandler(w http.ResponseWriter, r *http.Request) {
-	_, err := ioutil.ReadAll(r.Body)
+	_, err := io.ReadAll(r.Body)
 	if err != nil {
 		msg := fmt.Sprintf("Error reading body: %s", err.Error())
 		log.Printf(msg)
@@ -248,7 +248,7 @@ func RTMConnectHandler(w http.ResponseWriter, r *http.Request) {
 }
 
 func rtmStartHandler(w http.ResponseWriter, r *http.Request) {
-	_, err := ioutil.ReadAll(r.Body)
+	_, err := io.ReadAll(r.Body)
 	if err != nil {
 		msg := fmt.Sprintf("Error reading body: %s", err.Error())
 		log.Printf(msg)
diff --git a/users_test.go b/users_test.go
index 5ba915995..eedfd2d60 100644
--- a/users_test.go
+++ b/users_test.go
@@ -8,7 +8,6 @@ import (
 	"image/draw"
 	"image/png"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"reflect"
@@ -556,7 +555,7 @@ func setUserPhotoHandler(wantBytes []byte, wantParams UserSetPhotoParams) http.H
 			httpTestErrReply(w, true, fmt.Sprintf("failed to open uploaded file: %+v", err))
 			return
 		}
-		gotBytes, err := ioutil.ReadAll(file)
+		gotBytes, err := io.ReadAll(file)
 		if err != nil {
 			httpTestErrReply(w, true, fmt.Sprintf("failed to read uploaded file: %+v", err))
 			return
@@ -577,7 +576,7 @@ func createUserPhoto(t *testing.T) (*os.File, []byte, func()) {
 	photo := image.NewRGBA(image.Rect(0, 0, 64, 64))
 	draw.Draw(photo, photo.Bounds(), image.Black, image.ZP, draw.Src)
 
-	f, err := ioutil.TempFile(os.TempDir(), "profile.png")
+	f, err := os.CreateTemp(os.TempDir(), "profile.png")
 	if err != nil {
 		t.Fatalf("failed to create test photo: %+v\n", err)
 	}
diff --git a/webhooks.go b/webhooks.go
index 8fc149d90..5a854f38b 100644
--- a/webhooks.go
+++ b/webhooks.go
@@ -6,7 +6,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 )
 
@@ -57,7 +56,7 @@ func PostWebhookCustomHTTPContext(ctx context.Context, url string, httpClient *h
 		return fmt.Errorf("failed to post webhook: %w", err)
 	}
 	defer func() {
-		io.Copy(ioutil.Discard, resp.Body)
+		io.Copy(io.Discard, resp.Body)
 		resp.Body.Close()
 	}()