diff --git a/CHANGELOG.md b/CHANGELOG.md
index cd4682f2f..9fdd0a915 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -78,6 +78,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (x/slashing) [\#8427](https://github.com/cosmos/cosmos-sdk/pull/8427) Fix query signing infos command
 * (server) [\#8399](https://github.com/cosmos/cosmos-sdk/pull/8399) fix gRPC-web flag default value
 * (server) [\#8641](https://github.com/cosmos/cosmos-sdk/pull/8641) Fix Tendermint and application configuration reading from file
+* (rest) [\#8730](https://github.com/cosmos/cosmos-sdk/pull/8730) Fix querying txs with multisigs on legacy REST endpoints.
 * (client/keys) [\#8639] (https://github.com/cosmos/cosmos-sdk/pull/8639) Fix keys migrate for mulitisig, offline, and ledger keys. The migrate command now takes a positional old_home_dir argument.
 
 ## [v0.41.3](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.41.3) - 2021-02-18
diff --git a/x/auth/client/rest/rest_test.go b/x/auth/client/rest/rest_test.go
index cfca52750..9ecb3e842 100644
--- a/x/auth/client/rest/rest_test.go
+++ b/x/auth/client/rest/rest_test.go
@@ -2,6 +2,7 @@ package rest_test
 
 import (
 	"fmt"
+	"strings"
 	"testing"
 
 	"github.com/spf13/cobra"
@@ -11,6 +12,8 @@ import (
 	"github.com/cosmos/cosmos-sdk/client/tx"
 	"github.com/cosmos/cosmos-sdk/crypto/hd"
 	"github.com/cosmos/cosmos-sdk/crypto/keyring"
+	kmultisig "github.com/cosmos/cosmos-sdk/crypto/keys/multisig"
+	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
 	"github.com/cosmos/cosmos-sdk/testutil"
 	clitestutil "github.com/cosmos/cosmos-sdk/testutil/cli"
 	"github.com/cosmos/cosmos-sdk/testutil/network"
@@ -22,6 +25,7 @@ import (
 	authclient "github.com/cosmos/cosmos-sdk/x/auth/client"
 	authcli "github.com/cosmos/cosmos-sdk/x/auth/client/cli"
 	authrest "github.com/cosmos/cosmos-sdk/x/auth/client/rest"
+	authtest "github.com/cosmos/cosmos-sdk/x/auth/client/testutil"
 	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
 	bankcli "github.com/cosmos/cosmos-sdk/x/bank/client/testutil"
 	"github.com/cosmos/cosmos-sdk/x/bank/types"
@@ -52,6 +56,16 @@ func (s *IntegrationTestSuite) SetupSuite() {
 	_, _, err := kb.NewMnemonic("newAccount", keyring.English, sdk.FullFundraiserPath, keyring.DefaultBIP39Passphrase, hd.Secp256k1)
 	s.Require().NoError(err)
 
+	account1, _, err := kb.NewMnemonic("newAccount1", keyring.English, sdk.FullFundraiserPath, keyring.DefaultBIP39Passphrase, hd.Secp256k1)
+	s.Require().NoError(err)
+
+	account2, _, err := kb.NewMnemonic("newAccount2", keyring.English, sdk.FullFundraiserPath, keyring.DefaultBIP39Passphrase, hd.Secp256k1)
+	s.Require().NoError(err)
+
+	multi := kmultisig.NewLegacyAminoPubKey(2, []cryptotypes.PubKey{account1.GetPubKey(), account2.GetPubKey()})
+	_, err = kb.SaveMultisig("multi", multi)
+	s.Require().NoError(err)
+
 	_, err = s.network.WaitForHeight(1)
 	s.Require().NoError(err)
 
@@ -560,6 +574,97 @@ func (s *IntegrationTestSuite) TestLegacyRestErrMessages() {
 	}
 }
 
+// TestLegacyMultiSig creates a legacy multisig transaction, and makes sure
+// we can query it via the legacy REST endpoint.
+// ref: https://github.com/cosmos/cosmos-sdk/issues/8679
+func (s *IntegrationTestSuite) TestLegacyMultisig() {
+	val1 := *s.network.Validators[0]
+
+	// Generate 2 accounts and a multisig.
+	account1, err := val1.ClientCtx.Keyring.Key("newAccount1")
+	s.Require().NoError(err)
+
+	account2, err := val1.ClientCtx.Keyring.Key("newAccount2")
+	s.Require().NoError(err)
+
+	multisigInfo, err := val1.ClientCtx.Keyring.Key("multi")
+	s.Require().NoError(err)
+
+	// Send coins from validator to multisig.
+	sendTokens := sdk.NewInt64Coin(s.cfg.BondDenom, 1000)
+	_, err = bankcli.MsgSendExec(
+		val1.ClientCtx,
+		val1.Address,
+		multisigInfo.GetAddress(),
+		sdk.NewCoins(sendTokens),
+		fmt.Sprintf("--%s=true", flags.FlagSkipConfirmation),
+		fmt.Sprintf("--%s=%s", flags.FlagBroadcastMode, flags.BroadcastBlock),
+		fmt.Sprintf("--%s=%s", flags.FlagFees, sdk.NewCoins(sdk.NewCoin(s.cfg.BondDenom, sdk.NewInt(10))).String()),
+		fmt.Sprintf("--gas=%d", flags.DefaultGasLimit),
+	)
+
+	s.Require().NoError(s.network.WaitForNextBlock())
+
+	// Generate multisig transaction to a random address.
+	_, _, recipient := testdata.KeyTestPubAddr()
+	multiGeneratedTx, err := bankcli.MsgSendExec(
+		val1.ClientCtx,
+		multisigInfo.GetAddress(),
+		recipient,
+		sdk.NewCoins(
+			sdk.NewInt64Coin(s.cfg.BondDenom, 5),
+		),
+		fmt.Sprintf("--%s=true", flags.FlagSkipConfirmation),
+		fmt.Sprintf("--%s=%s", flags.FlagBroadcastMode, flags.BroadcastBlock),
+		fmt.Sprintf("--%s=%s", flags.FlagFees, sdk.NewCoins(sdk.NewCoin(s.cfg.BondDenom, sdk.NewInt(10))).String()),
+		fmt.Sprintf("--%s=true", flags.FlagGenerateOnly),
+	)
+	s.Require().NoError(err)
+
+	// Save tx to file
+	multiGeneratedTxFile := testutil.WriteToNewTempFile(s.T(), multiGeneratedTx.String())
+
+	// Sign with account1
+	val1.ClientCtx.HomeDir = strings.Replace(val1.ClientCtx.HomeDir, "simd", "simcli", 1)
+	account1Signature, err := authtest.TxSignExec(val1.ClientCtx, account1.GetAddress(), multiGeneratedTxFile.Name(), "--multisig", multisigInfo.GetAddress().String())
+	s.Require().NoError(err)
+
+	sign1File := testutil.WriteToNewTempFile(s.T(), account1Signature.String())
+
+	// Sign with account1
+	account2Signature, err := authtest.TxSignExec(val1.ClientCtx, account2.GetAddress(), multiGeneratedTxFile.Name(), "--multisig", multisigInfo.GetAddress().String())
+	s.Require().NoError(err)
+
+	sign2File := testutil.WriteToNewTempFile(s.T(), account2Signature.String())
+
+	// Does not work in offline mode.
+	_, err = authtest.TxMultiSignExec(val1.ClientCtx, multisigInfo.GetName(), multiGeneratedTxFile.Name(), "--offline", sign1File.Name(), sign2File.Name())
+	s.Require().EqualError(err, fmt.Sprintf("couldn't verify signature for address %s", account1.GetAddress()))
+
+	val1.ClientCtx.Offline = false
+	multiSigWith2Signatures, err := authtest.TxMultiSignExec(val1.ClientCtx, multisigInfo.GetName(), multiGeneratedTxFile.Name(), sign1File.Name(), sign2File.Name())
+	s.Require().NoError(err)
+
+	// Write the output to disk
+	signedTxFile := testutil.WriteToNewTempFile(s.T(), multiSigWith2Signatures.String())
+
+	_, err = authtest.TxValidateSignaturesExec(val1.ClientCtx, signedTxFile.Name())
+	s.Require().NoError(err)
+
+	val1.ClientCtx.BroadcastMode = flags.BroadcastBlock
+	out, err := authtest.TxBroadcastExec(val1.ClientCtx, signedTxFile.Name())
+	s.Require().NoError(err)
+
+	s.Require().NoError(s.network.WaitForNextBlock())
+
+	var txRes sdk.TxResponse
+	err = val1.ClientCtx.JSONMarshaler.UnmarshalJSON(out.Bytes(), &txRes)
+	s.Require().NoError(err)
+	s.Require().Equal(uint32(0), txRes.Code)
+
+	s.testQueryTx(txRes.Height, txRes.TxHash, recipient.String())
+}
+
 func TestIntegrationTestSuite(t *testing.T) {
 	suite.Run(t, new(IntegrationTestSuite))
 }
diff --git a/x/auth/legacy/legacytx/stdsign.go b/x/auth/legacy/legacytx/stdsign.go
index 466981369..f87900620 100644
--- a/x/auth/legacy/legacytx/stdsign.go
+++ b/x/auth/legacy/legacytx/stdsign.go
@@ -5,7 +5,6 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/codec"
 	"github.com/cosmos/cosmos-sdk/codec/legacy"
-	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
 	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
 	"github.com/cosmos/cosmos-sdk/crypto/types/multisig"
 	sdk "github.com/cosmos/cosmos-sdk/types"
@@ -13,9 +12,6 @@ import (
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
 )
 
-// Interface implementation checks
-var _ codectypes.UnpackInterfacesMessage = StdTx{}
-
 // StdSignDoc is replay-prevention structure.
 // It includes the result of msg.GetSignBytes(),
 // as well as the ChainID (prevent cross chain replay)
diff --git a/x/auth/legacy/legacytx/stdtx.go b/x/auth/legacy/legacytx/stdtx.go
index 8cb3fb699..2b8a6c0e0 100644
--- a/x/auth/legacy/legacytx/stdtx.go
+++ b/x/auth/legacy/legacytx/stdtx.go
@@ -16,9 +16,12 @@ import (
 
 // Interface implementation checks
 var (
-	_ sdk.Tx         = (*StdTx)(nil)
-	_ sdk.TxWithMemo = (*StdTx)(nil)
-	_ sdk.FeeTx      = (*StdTx)(nil)
+	_ sdk.Tx                             = (*StdTx)(nil)
+	_ sdk.TxWithMemo                     = (*StdTx)(nil)
+	_ sdk.FeeTx                          = (*StdTx)(nil)
+	_ codectypes.UnpackInterfacesMessage = (*StdTx)(nil)
+
+	_ codectypes.UnpackInterfacesMessage = (*StdSignature)(nil)
 )
 
 // StdFee includes the amount of coins paid in fees and the maximum
@@ -116,6 +119,10 @@ func (ss StdSignature) MarshalYAML() (interface{}, error) {
 	return string(bz), err
 }
 
+func (ss StdSignature) UnpackInterfaces(unpacker codectypes.AnyUnpacker) error {
+	return codectypes.UnpackInterfaces(ss.PubKey, unpacker)
+}
+
 // StdTx is the legacy transaction format for wrapping a Msg with Fee and Signatures.
 // It only works with Amino, please prefer the new protobuf Tx in types/tx.
 // NOTE: the first signature is the fee payer (Signatures must not be nil).
@@ -277,5 +284,14 @@ func (tx StdTx) UnpackInterfaces(unpacker codectypes.AnyUnpacker) error {
 			return err
 		}
 	}
+
+	// Signatures contain PubKeys, which need to be unpacked.
+	for _, s := range tx.Signatures {
+		err := codectypes.UnpackInterfaces(s, unpacker)
+		if err != nil {
+			return err
+		}
+	}
+
 	return nil
 }