diff --git a/shared/featureconfig/config.go b/shared/featureconfig/config.go
index cb7f38360..daa8684ef 100644
--- a/shared/featureconfig/config.go
+++ b/shared/featureconfig/config.go
@@ -34,6 +34,7 @@ type Flags struct {
 	NewBeaconStateLocks bool // NewStateLocks for updated beacon state locking.
 	// Testnet Flags.
 	AltonaTestnet bool // AltonaTestnet defines the flag through which we can enable the node to run on the altona testnet.
+	OnyxTestnet   bool // OnyxTestnet defines the flag through which we can enable the node to run on the onyx testnet.
 	// Feature related flags.
 	WriteSSZStateTransitions                   bool // WriteSSZStateTransitions to tmp directory.
 	InitSyncNoVerify                           bool // InitSyncNoVerify when initial syncing w/o verifying block's contents.
@@ -124,6 +125,12 @@ func ConfigureBeaconChain(ctx *cli.Context) {
 		params.UseAltonaNetworkConfig()
 		cfg.AltonaTestnet = true
 	}
+	if ctx.Bool(OnyxTestnet.Name) {
+		log.Warn("Running Node on Onyx Testnet")
+		params.UseOnyxConfig()
+		params.UseOnyxNetworkConfig()
+		cfg.OnyxTestnet = true
+	}
 	if ctx.Bool(writeSSZStateTransitionsFlag.Name) {
 		log.Warn("Writing SSZ states and blocks after state transitions")
 		cfg.WriteSSZStateTransitions = true
@@ -277,6 +284,12 @@ func ConfigureValidator(ctx *cli.Context) {
 		params.UseAltonaNetworkConfig()
 		cfg.AltonaTestnet = true
 	}
+	if ctx.Bool(OnyxTestnet.Name) {
+		log.Warn("Running Node on Onyx Testnet")
+		params.UseOnyxConfig()
+		params.UseOnyxNetworkConfig()
+		cfg.OnyxTestnet = true
+	}
 	if ctx.Bool(enableLocalProtectionFlag.Name) {
 		cfg.LocalProtection = true
 	} else {
diff --git a/shared/featureconfig/flags.go b/shared/featureconfig/flags.go
index cf3bc4bb9..533f49532 100644
--- a/shared/featureconfig/flags.go
+++ b/shared/featureconfig/flags.go
@@ -10,6 +10,11 @@ var (
 		Name:  "altona",
 		Usage: "This defines the flag through which we can run on the Altona Multiclient Testnet",
 	}
+	// OnyxTestnet flag for the Prysmatic Labs single-client testnet configuration.
+	OnyxTestnet = &cli.BoolFlag{
+		Name:  "onyx",
+		Usage: "This defines the flag through which we can run on the Onyx Prysm Testnet",
+	}
 	devModeFlag = &cli.BoolFlag{
 		Name:  "dev",
 		Usage: "Enable experimental features still in development. These features may not be stable.",
@@ -583,6 +588,7 @@ var ValidatorFlags = append(deprecatedFlags, []cli.Flag{
 	disableDomainDataCacheFlag,
 	waitForSyncedFlag,
 	AltonaTestnet,
+	OnyxTestnet,
 	disableAccountsV2,
 }...)
 
@@ -626,6 +632,7 @@ var BeaconChainFlags = append(deprecatedFlags, []cli.Flag{
 	newBeaconStateLocks,
 	forceMaxCoverAttestationAggregation,
 	AltonaTestnet,
+	OnyxTestnet,
 	batchBlockVerify,
 	initSyncVerbose,
 	enableFinalizedDepositsCache,
diff --git a/validator/accounts/v2/cmd_accounts.go b/validator/accounts/v2/cmd_accounts.go
index c0f1f8e79..661fb007e 100644
--- a/validator/accounts/v2/cmd_accounts.go
+++ b/validator/accounts/v2/cmd_accounts.go
@@ -24,6 +24,7 @@ this command outputs a deposit data string which is required to become a validat
 				flags.AccountPasswordFileFlag,
 				flags.NumAccountsFlag,
 				featureconfig.AltonaTestnet,
+				featureconfig.OnyxTestnet,
 			},
 			Action: func(cliCtx *cli.Context) error {
 				if err := CreateAccount(cliCtx); err != nil {
@@ -40,6 +41,7 @@ this command outputs a deposit data string which is required to become a validat
 				flags.WalletPasswordFileFlag,
 				flags.ShowDepositDataFlag,
 				featureconfig.AltonaTestnet,
+				featureconfig.OnyxTestnet,
 			},
 			Action: func(cliCtx *cli.Context) error {
 				if err := ListAccounts(cliCtx); err != nil {
@@ -56,6 +58,7 @@ this command outputs a deposit data string which is required to become a validat
 				flags.BackupDirFlag,
 				flags.AccountsFlag,
 				featureconfig.AltonaTestnet,
+				featureconfig.OnyxTestnet,
 			},
 			Action: func(cliCtx *cli.Context) error {
 				if err := ExportAccount(cliCtx); err != nil {
@@ -73,6 +76,7 @@ this command outputs a deposit data string which is required to become a validat
 				flags.KeysDirFlag,
 				flags.WalletPasswordFileFlag,
 				featureconfig.AltonaTestnet,
+				featureconfig.OnyxTestnet,
 			},
 			Action: func(cliCtx *cli.Context) error {
 				if err := ImportAccount(cliCtx); err != nil {
diff --git a/validator/accounts/v2/cmd_wallet.go b/validator/accounts/v2/cmd_wallet.go
index c526a8706..a0c8d3390 100644
--- a/validator/accounts/v2/cmd_wallet.go
+++ b/validator/accounts/v2/cmd_wallet.go
@@ -26,6 +26,7 @@ var WalletCommands = &cli.Command{
 				flags.RemoteSignerCACertPathFlag,
 				flags.WalletPasswordFileFlag,
 				featureconfig.AltonaTestnet,
+				featureconfig.OnyxTestnet,
 			},
 			Action: func(cliCtx *cli.Context) error {
 				if _, err := CreateWallet(cliCtx); err != nil {
@@ -45,6 +46,7 @@ var WalletCommands = &cli.Command{
 				flags.RemoteSignerCACertPathFlag,
 				flags.WalletPasswordsDirFlag,
 				featureconfig.AltonaTestnet,
+				featureconfig.OnyxTestnet,
 			},
 			Action: func(cliCtx *cli.Context) error {
 				if err := EditWalletConfiguration(cliCtx); err != nil {
@@ -63,6 +65,7 @@ var WalletCommands = &cli.Command{
 				flags.WalletPasswordFileFlag,
 				flags.NumAccountsFlag,
 				featureconfig.AltonaTestnet,
+				featureconfig.OnyxTestnet,
 			},
 			Action: func(cliCtx *cli.Context) error {
 				if err := RecoverWallet(cliCtx); err != nil {