diff --git a/.pending/bugfixes/sdk/4455-Print-null-whil b/.pending/bugfixes/sdk/4455-Print-null-whil
new file mode 100644
index 000000000000..c2761bec27af
--- /dev/null
+++ b/.pending/bugfixes/sdk/4455-Print-null-whil
@@ -0,0 +1 @@
+#4455 Use `QueryWithData()` to query unbonding delegations.
\ No newline at end of file
diff --git a/x/staking/client/cli/query.go b/x/staking/client/cli/query.go
index cfe526592d61..f829d9b87c6e 100644
--- a/x/staking/client/cli/query.go
+++ b/x/staking/client/cli/query.go
@@ -311,7 +311,7 @@ $ %s query staking delegations-to cosmosvaloper1gghjut3ccd8ay0zduzj64hwre2fxs9ld
 
 // GetCmdQueryUnbondingDelegation implements the command to query a single
 // unbonding-delegation record.
-func GetCmdQueryUnbondingDelegation(storeName string, cdc *codec.Codec) *cobra.Command {
+func GetCmdQueryUnbondingDelegation(storeKey string, cdc *codec.Codec) *cobra.Command {
 	return &cobra.Command{
 		Use:   "unbonding-delegation [delegator-addr] [validator-addr]",
 		Short: "Query an unbonding-delegation record based on delegator and validator address",
@@ -338,20 +338,25 @@ $ %s query staking unbonding-delegation cosmos1gghjut3ccd8ay0zduzj64hwre2fxs9ld7
 				return err
 			}
 
-			res, err := cliCtx.QueryStore(types.GetUBDKey(delAddr, valAddr), storeName)
+			bz, err := cdc.MarshalJSON(querier.NewQueryBondsParams(delAddr, valAddr))
 			if err != nil {
 				return err
 			}
 
-			return cliCtx.PrintOutput(types.MustUnmarshalUBD(cdc, res))
+			route := fmt.Sprintf("custom/%s/%s", storeKey, querier.QueryUnbondingDelegation)
+			res, err := cliCtx.QueryWithData(route, bz)
+			if err != nil {
+				return err
+			}
 
+			return cliCtx.PrintOutput(types.MustUnmarshalUBD(cdc, res))
 		},
 	}
 }
 
 // GetCmdQueryUnbondingDelegations implements the command to query all the
 // unbonding-delegation records for a delegator.
-func GetCmdQueryUnbondingDelegations(storeName string, cdc *codec.Codec) *cobra.Command {
+func GetCmdQueryUnbondingDelegations(storeKey string, cdc *codec.Codec) *cobra.Command {
 	return &cobra.Command{
 		Use:   "unbonding-delegations [delegator-addr]",
 		Short: "Query all unbonding-delegations records for one delegator",
@@ -373,14 +378,20 @@ $ %s query staking unbonding-delegation cosmos1gghjut3ccd8ay0zduzj64hwre2fxs9ld7
 				return err
 			}
 
-			resKVs, err := cliCtx.QuerySubspace(types.GetUBDsKey(delegatorAddr), storeName)
+			bz, err := cdc.MarshalJSON(querier.NewQueryDelegatorParams(delegatorAddr))
+			if err != nil {
+				return err
+			}
+
+			route := fmt.Sprintf("custom/%s/%s", storeKey, querier.QueryDelegatorUnbondingDelegations)
+			res, err := cliCtx.QueryWithData(route, bz)
 			if err != nil {
 				return err
 			}
 
 			var ubds types.UnbondingDelegations
-			for _, kv := range resKVs {
-				ubds = append(ubds, types.MustUnmarshalUBD(cdc, kv.Value))
+			if err = cdc.UnmarshalJSON(res, &ubds); err != nil {
+				return err
 			}
 
 			return cliCtx.PrintOutput(ubds)
diff --git a/x/staking/querier/querier_test.go b/x/staking/querier/querier_test.go
index 515cfcab326b..5a199c1dcca3 100644
--- a/x/staking/querier/querier_test.go
+++ b/x/staking/querier/querier_test.go
@@ -461,3 +461,94 @@ func TestQueryRedelegations(t *testing.T) {
 	require.Equal(t, redel.ValidatorDstAddress, redelRes[0].ValidatorDstAddress)
 	require.Len(t, redel.Entries, len(redelRes[0].Entries))
 }
+
+func TestQueryUnbondingDelegation(t *testing.T) {
+	cdc := codec.New()
+	ctx, _, keeper := keep.CreateTestInput(t, false, 10000)
+
+	// Create Validators and Delegation
+	val1 := types.NewValidator(addrVal1, pk1, types.Description{})
+	keeper.SetValidator(ctx, val1)
+
+	// delegate
+	delAmount := sdk.TokensFromTendermintPower(100)
+	_, err := keeper.Delegate(ctx, addrAcc1, delAmount, val1, true)
+	require.NoError(t, err)
+	_ = keeper.ApplyAndReturnValidatorSetUpdates(ctx)
+
+	// undelegate
+	undelAmount := sdk.TokensFromTendermintPower(20)
+	_, err = keeper.Undelegate(ctx, addrAcc1, val1.GetOperator(), undelAmount.ToDec())
+	require.NoError(t, err)
+	keeper.ApplyAndReturnValidatorSetUpdates(ctx)
+
+	_, found := keeper.GetUnbondingDelegation(ctx, addrAcc1, val1.OperatorAddress)
+	require.True(t, found)
+
+	//
+	// found: query unbonding delegation by delegator and validator
+	//
+	queryValidatorParams := NewQueryBondsParams(addrAcc1, val1.GetOperator())
+	bz, errRes := cdc.MarshalJSON(queryValidatorParams)
+	require.Nil(t, errRes)
+	query := abci.RequestQuery{
+		Path: "/custom/staking/unbondingDelegation",
+		Data: bz,
+	}
+	res, err := queryUnbondingDelegation(ctx, query, keeper)
+	require.Nil(t, err)
+	require.NotNil(t, res)
+	var ubDel types.UnbondingDelegation
+	require.NoError(t, cdc.UnmarshalJSON(res, &ubDel))
+	require.Equal(t, addrAcc1, ubDel.DelegatorAddress)
+	require.Equal(t, val1.OperatorAddress, ubDel.ValidatorAddress)
+	require.Equal(t, 1, len(ubDel.Entries))
+
+	//
+	// not found: query unbonding delegation by delegator and validator
+	//
+	queryValidatorParams = NewQueryBondsParams(addrAcc2, val1.GetOperator())
+	bz, errRes = cdc.MarshalJSON(queryValidatorParams)
+	require.Nil(t, errRes)
+	query = abci.RequestQuery{
+		Path: "/custom/staking/unbondingDelegation",
+		Data: bz,
+	}
+	res, err = queryUnbondingDelegation(ctx, query, keeper)
+	require.NotNil(t, err)
+
+	//
+	// found: query unbonding delegation by delegator and validator
+	//
+	queryDelegatorParams := NewQueryDelegatorParams(addrAcc1)
+	bz, errRes = cdc.MarshalJSON(queryDelegatorParams)
+	require.Nil(t, errRes)
+	query = abci.RequestQuery{
+		Path: "/custom/staking/delegatorUnbondingDelegations",
+		Data: bz,
+	}
+	res, err = queryDelegatorUnbondingDelegations(ctx, query, keeper)
+	require.Nil(t, err)
+	require.NotNil(t, res)
+	var ubDels []types.UnbondingDelegation
+	require.NoError(t, cdc.UnmarshalJSON(res, &ubDels))
+	require.Equal(t, 1, len(ubDels))
+	require.Equal(t, addrAcc1, ubDels[0].DelegatorAddress)
+	require.Equal(t, val1.OperatorAddress, ubDels[0].ValidatorAddress)
+
+	//
+	// not found: query unbonding delegation by delegator and validator
+	//
+	queryDelegatorParams = NewQueryDelegatorParams(addrAcc2)
+	bz, errRes = cdc.MarshalJSON(queryDelegatorParams)
+	require.Nil(t, errRes)
+	query = abci.RequestQuery{
+		Path: "/custom/staking/delegatorUnbondingDelegations",
+		Data: bz,
+	}
+	res, err = queryDelegatorUnbondingDelegations(ctx, query, keeper)
+	require.Nil(t, err)
+	require.NotNil(t, res)
+	require.NoError(t, cdc.UnmarshalJSON(res, &ubDels))
+	require.Equal(t, 0, len(ubDels))
+}