diff --git a/packages/transaction-controller/CHANGELOG.md b/packages/transaction-controller/CHANGELOG.md
index c2fdc4e93ee..b57f1c659c8 100644
--- a/packages/transaction-controller/CHANGELOG.md
+++ b/packages/transaction-controller/CHANGELOG.md
@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add `SEI` network support ([#5694](https://github.com/MetaMask/core/pull/5694))
+  - Add account address relationship API support
+  - Add incoming transactions API support
+
 ## [54.1.0]
 
 ### Changed
diff --git a/packages/transaction-controller/src/api/accounts-api.ts b/packages/transaction-controller/src/api/accounts-api.ts
index 39231916c55..aabe4a88aa7 100644
--- a/packages/transaction-controller/src/api/accounts-api.ts
+++ b/packages/transaction-controller/src/api/accounts-api.ts
@@ -106,6 +106,7 @@ const SUPPORTED_CHAIN_IDS_FOR_RELATIONSHIP_API = [
   42161, // Arbitrum
   59144, // Linea
   534352, // Scroll
+  1329, // Sei
 ];
 
 const log = createModuleLogger(projectLogger, 'accounts-api');
diff --git a/packages/transaction-controller/src/constants.ts b/packages/transaction-controller/src/constants.ts
index 1ef5a7f5728..fa9042da667 100644
--- a/packages/transaction-controller/src/constants.ts
+++ b/packages/transaction-controller/src/constants.ts
@@ -30,6 +30,7 @@ export const CHAIN_IDS = {
   SCROLL: '0x82750',
   SCROLL_SEPOLIA: '0x8274f',
   MEGAETH_TESTNET: '0x18c6',
+  SEI: '0x539',
 } as const;
 
 /** Extract of the Wrapped ERC-20 ABI required for simulation. */
diff --git a/packages/transaction-controller/src/helpers/AccountsApiRemoteTransactionSource.ts b/packages/transaction-controller/src/helpers/AccountsApiRemoteTransactionSource.ts
index 2f6faf29f81..b37d2c4a866 100644
--- a/packages/transaction-controller/src/helpers/AccountsApiRemoteTransactionSource.ts
+++ b/packages/transaction-controller/src/helpers/AccountsApiRemoteTransactionSource.ts
@@ -29,6 +29,7 @@ export const SUPPORTED_CHAIN_IDS: Hex[] = [
   CHAIN_IDS.OPTIMISM,
   CHAIN_IDS.ARBITRUM,
   CHAIN_IDS.SCROLL,
+  CHAIN_IDS.SEI,
 ];
 
 const log = createModuleLogger(
diff --git a/packages/transaction-controller/src/utils/swaps.ts b/packages/transaction-controller/src/utils/swaps.ts
index e0cc8e51d8d..a239ba88f25 100644
--- a/packages/transaction-controller/src/utils/swaps.ts
+++ b/packages/transaction-controller/src/utils/swaps.ts
@@ -94,6 +94,12 @@ const ZKSYNC_ERA_SWAPS_TOKEN_OBJECT: SwapsTokenObject = {
   ...ETH_SWAPS_TOKEN_OBJECT,
 } as const;
 
+const SEI_SWAPS_TOKEN_OBJECT: SwapsTokenObject = {
+  name: 'Sei',
+  address: DEFAULT_TOKEN_ADDRESS,
+  decimals: 18,
+} as const;
+
 export const SWAPS_CHAINID_DEFAULT_TOKEN_MAP = {
   [CHAIN_IDS.MAINNET]: ETH_SWAPS_TOKEN_OBJECT,
   [SWAPS_TESTNET_CHAIN_ID]: TEST_ETH_SWAPS_TOKEN_OBJECT,
@@ -104,6 +110,7 @@ export const SWAPS_CHAINID_DEFAULT_TOKEN_MAP = {
   [CHAIN_IDS.OPTIMISM]: OPTIMISM_SWAPS_TOKEN_OBJECT,
   [CHAIN_IDS.ARBITRUM]: ARBITRUM_SWAPS_TOKEN_OBJECT,
   [CHAIN_IDS.ZKSYNC_ERA]: ZKSYNC_ERA_SWAPS_TOKEN_OBJECT,
+  [CHAIN_IDS.SEI]: SEI_SWAPS_TOKEN_OBJECT,
 } as const;
 
 export const SWAP_TRANSACTION_TYPES = [