diff --git a/pkg/executor/insert.go b/pkg/executor/insert.go
index c10c7810f01e4..22dd28c673c1e 100644
--- a/pkg/executor/insert.go
+++ b/pkg/executor/insert.go
@@ -186,7 +186,7 @@ func (e *InsertValues) prefetchDataCache(ctx context.Context, txn kv.Transaction
 }
 
 // updateDupRow updates a duplicate row to a new row.
-func (e *InsertExec) updateDupRow(ctx context.Context, idxInBatch int, txn kv.Transaction, row toBeCheckedRow, handle kv.Handle, _ []*expression.Assignment) error {
+func (e *InsertExec) updateDupRow(ctx context.Context, idxInBatch int, txn kv.Transaction, row toBeCheckedRow, handle kv.Handle, _ []*expression.Assignment, autoColIdx int) error {
 	oldRow, err := getOldRow(ctx, e.Ctx(), txn, row.t, handle, e.GenExprs)
 	if err != nil {
 		return err
@@ -197,7 +197,7 @@ func (e *InsertExec) updateDupRow(ctx context.Context, idxInBatch int, txn kv.Tr
 		extraCols = e.Ctx().GetSessionVars().CurrInsertBatchExtraCols[idxInBatch]
 	}
 
-	err = e.doDupRowUpdate(ctx, handle, oldRow, row.row, extraCols, e.OnDuplicate, idxInBatch)
+	err = e.doDupRowUpdate(ctx, handle, oldRow, row.row, extraCols, e.OnDuplicate, idxInBatch, autoColIdx)
 	if e.Ctx().GetSessionVars().StmtCtx.DupKeyAsWarning && (kv.ErrKeyExists.Equal(err) ||
 		table.ErrCheckConstraintViolated.Equal(err)) {
 		e.Ctx().GetSessionVars().StmtCtx.AppendWarning(err)
@@ -236,6 +236,11 @@ func (e *InsertExec) batchUpdateDupRows(ctx context.Context, newRows [][]types.D
 		e.stats.Prefetch += time.Since(prefetchStart)
 	}
 
+	_, autoColIdx, found := findAutoIncrementColumn(e.Table)
+	if !found {
+		autoColIdx = -1
+	}
+
 	for i, r := range toBeCheckedRows {
 		if r.handleKey != nil {
 			handle, err := tablecodec.DecodeRowKey(r.handleKey.newKey)
@@ -243,7 +248,7 @@ func (e *InsertExec) batchUpdateDupRows(ctx context.Context, newRows [][]types.D
 				return err
 			}
 
-			err = e.updateDupRow(ctx, i, txn, r, handle, e.OnDuplicate)
+			err = e.updateDupRow(ctx, i, txn, r, handle, e.OnDuplicate, autoColIdx)
 			if err == nil {
 				continue
 			}
@@ -260,7 +265,7 @@ func (e *InsertExec) batchUpdateDupRows(ctx context.Context, newRows [][]types.D
 			if handle == nil {
 				continue
 			}
-			err = e.updateDupRow(ctx, i, txn, r, handle, e.OnDuplicate)
+			err = e.updateDupRow(ctx, i, txn, r, handle, e.OnDuplicate, autoColIdx)
 			if err != nil {
 				if kv.IsErrNotFound(err) {
 					// Data index inconsistent? A unique key provide the handle information, but the
@@ -381,7 +386,7 @@ func (e *InsertExec) initEvalBuffer4Dup() {
 
 // doDupRowUpdate updates the duplicate row.
 func (e *InsertExec) doDupRowUpdate(ctx context.Context, handle kv.Handle, oldRow []types.Datum, newRow []types.Datum,
-	extraCols []types.Datum, cols []*expression.Assignment, idxInBatch int) error {
+	extraCols []types.Datum, cols []*expression.Assignment, idxInBatch int, autoColIdx int) error {
 	assignFlag := make([]bool, len(e.Table.WritableCols()))
 	// See http://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_values
 	e.curInsertVals.SetDatums(newRow...)
@@ -430,6 +435,17 @@ func (e *InsertExec) doDupRowUpdate(ctx context.Context, handle kv.Handle, oldRo
 	if err != nil {
 		return err
 	}
+
+	if autoColIdx >= 0 {
+		if e.Ctx().GetSessionVars().StmtCtx.AffectedRows() > 0 {
+			// If "INSERT ... ON DUPLICATE KEY UPDATE" duplicate and update a row,
+			// auto increment value should be set correctly for mysql_insert_id()
+			// See https://github.com/pingcap/tidb/issues/55965
+			e.Ctx().GetSessionVars().StmtCtx.InsertID = newData[autoColIdx].GetUint64()
+		} else {
+			e.Ctx().GetSessionVars().StmtCtx.InsertID = 0
+		}
+	}
 	return nil
 }
 
diff --git a/pkg/executor/insert_test.go b/pkg/executor/insert_test.go
index 6cfa7fb258ad8..4f88cc09cb4f7 100644
--- a/pkg/executor/insert_test.go
+++ b/pkg/executor/insert_test.go
@@ -1628,3 +1628,68 @@ func TestUnsignedDecimalFloatInsertNegative(t *testing.T) {
 	tk.MustExec("insert into tf values('-100')")
 	tk.MustQuery("select * from tf").Check(testkit.Rows("0"))
 }
+
+func TestMySQLInsertID(t *testing.T) {
+	// mysql_insert_id() differs from LAST_INSERT_ID()
+	// See https://github.com/pingcap/tidb/issues/55965
+	// mysql_insert_id() is got from tk.Session().LastInsertID()
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec(`use test`)
+	tk.MustExec("drop table if exists tb")
+	tk.MustExec("create table tb(pk int primary key auto_increment, a int, b int, unique(a))")
+	defer tk.MustExec("drop table if exists tb")
+
+	tk.MustExec("insert into tb (a, b) values (1, 1) on duplicate key update b = values(b)")
+	require.Equal(t, tk.Session().LastInsertID(), uint64(1))
+
+	tk.MustExec("insert into tb (a, b) values (2, 2) on duplicate key update b = values(b)")
+	require.Equal(t, tk.Session().LastInsertID(), uint64(2))
+
+	// If there is an AUTO_INCREMENT column in the table and there were some explicit successfully
+	// inserted values or some updated values, return the last of the inserted or updated values.
+	// Ref https://dev.mysql.com/doc/c-api/5.7/en/mysql-insert-id.html#:~:text=When%20called%20after%20an%20INSERT%20...%20ON,of%20the%20inserted%20or%20updated%20values
+	tk.MustExec("insert into tb (a, b) values (1, 2) on duplicate key update b = values(b)")
+	require.Equal(t, tk.Session().LastInsertID(), uint64(1))
+	tk.MustQuery("select LAST_INSERT_ID()").Check(testkit.Rows("2"))
+
+	tk.MustQuery("select * from tb").Sort().Check(testkit.Rows("1 1 2", "2 2 2"))
+
+	// When the new row and the old row are exactly the same (no inserted or updated values), mysql_insert_id() is 0
+	tk.MustExec("insert into tb (a, b) values (1, 2) on duplicate key update b = 2")
+	require.Equal(t, tk.Session().LastInsertID(), uint64(0))
+	tk.MustQuery("select LAST_INSERT_ID()").Check(testkit.Rows("2"))
+
+	// When the value of auto increment column is assigned explicitly, LAST_INSERT_ID() is unchanged.
+	// mysql_insert_id() is set to the explicit assigned value.
+	tk.MustExec("insert into tb values (6, 6, 6)")
+	require.Equal(t, tk.Session().LastInsertID(), uint64(6))
+	tk.MustQuery("select LAST_INSERT_ID()").Check(testkit.Rows("2"))
+
+	// Update statement touches neigher mysql_insert_id() nor LAST_INSERT_ID()
+	tk.MustExec("update tb set b = 7, pk = pk + 1 where b = 6")
+	require.Equal(t, tk.Session().LastInsertID(), uint64(0))
+	tk.MustQuery("select LAST_INSERT_ID()").Check(testkit.Rows("2"))
+
+	// How to distinguish LAST_INSERT_ID() and mysql_insert_id()?
+	// In a word, LAST_INSERT_ID() is always get from auto allocated value, while mysql_insert_id() can be
+	// auto allocated or explicited specified.
+
+	// Another scenario mentioned by @lcwangcao
+	// What's the behaviour when transaction conflict involved?
+	tk.MustExec("truncate table tb")
+	tk.MustExec("insert into tb (a, b) values (1, 1), (2, 2)")
+
+	tk1 := testkit.NewTestKit(t, store)
+	tk1.MustExec("use test")
+	tk1.MustExec("begin")
+	tk1.MustExec("update tb set b = 2 where a = 1")
+	go func() {
+		time.Sleep(100 * time.Millisecond)
+		tk1.MustExec("commit")
+	}()
+	// The first time this will update one row.
+	// Then transaction conflict and retry, in the second time it modify nothing.
+	tk.MustExec("insert into tb(a, b) values(1,2) on duplicate key update b = 2;")
+	require.Equal(t, tk.Session().LastInsertID(), uint64(0))
+}