diff --git a/cmd/root.go b/cmd/root.go
index 9552a96..e972a95 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -102,6 +102,7 @@ func init() {
 	rootCmd.Flags().StringVar(&config.SMTPTLSKey, "smtp-tls-key", config.SMTPTLSKey, "TLS key for SMTP (STARTTLS) - requires smtp-tls-cert")
 	rootCmd.Flags().BoolVar(&config.SMTPAuthAllowInsecure, "smtp-auth-allow-insecure", config.SMTPAuthAllowInsecure, "Enable insecure PLAIN & LOGIN authentication")
 	rootCmd.Flags().BoolVar(&config.SMTPStrictRFCHeaders, "smtp-strict-rfc-headers", config.SMTPStrictRFCHeaders, "Return SMTP error if message headers contain <CR><CR><LF>")
+	rootCmd.Flags().IntVar(&config.SMTPMaxRecipients, "smtp-max-recipients", config.SMTPMaxRecipients, "Maximum SMTP recipients allowed")
 
 	rootCmd.Flags().StringVar(&config.SMTPRelayConfigFile, "smtp-relay-config", config.SMTPRelayConfigFile, "SMTP configuration file to allow releasing messages")
 	rootCmd.Flags().BoolVar(&config.SMTPRelayAllIncoming, "smtp-relay-all", config.SMTPRelayAllIncoming, "Relay all incoming messages via external SMTP server (caution!)")
@@ -166,6 +167,9 @@ func initConfigFromEnv() {
 	if getEnabledFromEnv("MP_SMTP_STRICT_RFC_HEADERS") {
 		config.SMTPStrictRFCHeaders = true
 	}
+	if len(os.Getenv("MP_SMTP_MAX_RECIPIENTS")) > 0 {
+		config.SMTPMaxRecipients, _ = strconv.Atoi(os.Getenv("MP_SMTP_MAX_RECIPIENTS"))
+	}
 
 	// Relay server config
 	config.SMTPRelayConfigFile = os.Getenv("MP_SMTP_RELAY_CONFIG")
diff --git a/config/config.go b/config/config.go
index 97406a5..c8e7011 100644
--- a/config/config.go
+++ b/config/config.go
@@ -60,6 +60,11 @@ var (
 	// SMTPAuthAcceptAny accepts any username/password including none
 	SMTPAuthAcceptAny bool
 
+	// SMTPMaxRecipients is the maximum number of recipients a message may have.
+	// The SMTP RFC states that an server must handle a minimum of 100 recipients
+	// however some servers accept more.
+	SMTPMaxRecipients = 100
+
 	// IgnoreDuplicateIDs will skip messages with the same ID
 	IgnoreDuplicateIDs bool
 
diff --git a/go.mod b/go.mod
index 29ff269..b806b8b 100644
--- a/go.mod
+++ b/go.mod
@@ -14,7 +14,7 @@ require (
 	github.com/jhillyerd/enmime v1.0.1
 	github.com/klauspost/compress v1.17.4
 	github.com/leporo/sqlf v1.4.0
-	github.com/mhale/smtpd v0.8.0
+	github.com/mhale/smtpd v0.8.1
 	github.com/reiver/go-telnet v0.0.0-20180421082511-9ff0b2ab096e
 	github.com/sirupsen/logrus v1.9.3
 	github.com/spf13/cobra v1.8.0
diff --git a/go.sum b/go.sum
index 8b080c0..e075938 100644
--- a/go.sum
+++ b/go.sum
@@ -90,8 +90,8 @@ github.com/mattn/go-runewidth v0.0.15 h1:UNAjwbU9l54TA3KzvqLGxwWjHmMgBUVhBiTjelZ
 github.com/mattn/go-runewidth v0.0.15/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
 github.com/mattn/go-sqlite3 v1.14.16 h1:yOQRA0RpS5PFz/oikGwBEqvAWhWg5ufRz4ETLjwpU1Y=
 github.com/mattn/go-sqlite3 v1.14.16/go.mod h1:2eHXhiwb8IkHr+BDWZGa96P6+rkvnG63S2DGjv9HUNg=
-github.com/mhale/smtpd v0.8.0 h1:5JvdsehCg33PQrZBvFyDMMUDQmvbzVpZgKob7eYBJc0=
-github.com/mhale/smtpd v0.8.0/go.mod h1:MQl+y2hwIEQCXtNhe5+55n0GZOjSmeqORDIXbqUL3x4=
+github.com/mhale/smtpd v0.8.1 h1:O02u8O3eYAGxZCGf4E98WjyB+rA3DVFZtchEialjX4s=
+github.com/mhale/smtpd v0.8.1/go.mod h1:MQl+y2hwIEQCXtNhe5+55n0GZOjSmeqORDIXbqUL3x4=
 github.com/olekukonko/tablewriter v0.0.5 h1:P2Ga83D34wi1o9J6Wh1mRuqd4mF/x/lgBS7N7AbDhec=
 github.com/olekukonko/tablewriter v0.0.5/go.mod h1:hPp6KlRPjbx+hW8ykQs1w3UBbZlj6HuIJcUGPhkA7kY=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
diff --git a/server/smtpd/smtpd.go b/server/smtpd/smtpd.go
index 21b9a0d..2a37582 100644
--- a/server/smtpd/smtpd.go
+++ b/server/smtpd/smtpd.go
@@ -170,12 +170,13 @@ func Listen() error {
 
 func listenAndServe(addr string, handler smtpd.Handler, authHandler smtpd.AuthHandler) error {
 	srv := &smtpd.Server{
-		Addr:         addr,
-		Handler:      handler,
-		Appname:      "Mailpit",
-		Hostname:     "",
-		AuthHandler:  nil,
-		AuthRequired: false,
+		Addr:          addr,
+		Handler:       handler,
+		Appname:       "Mailpit",
+		Hostname:      "",
+		AuthHandler:   nil,
+		AuthRequired:  false,
+		MaxRecipients: config.SMTPMaxRecipients,
 	}
 
 	if config.SMTPAuthAllowInsecure {