diff --git a/ingestion/src/metadata/ingestion/source/dashboard/quicksight/metadata.py b/ingestion/src/metadata/ingestion/source/dashboard/quicksight/metadata.py
index 384b27fd189d..89947300c4bf 100644
--- a/ingestion/src/metadata/ingestion/source/dashboard/quicksight/metadata.py
+++ b/ingestion/src/metadata/ingestion/source/dashboard/quicksight/metadata.py
@@ -45,13 +45,18 @@
     SourceUrl,
     Uuid,
 )
-from metadata.generated.schema.type.entityLineage import EntitiesEdge, LineageDetails
+from metadata.generated.schema.type.entityLineage import (
+    ColumnLineage,
+    EntitiesEdge,
+    LineageDetails,
+)
 from metadata.generated.schema.type.entityLineage import Source as LineageSource
 from metadata.generated.schema.type.entityReference import EntityReference
 from metadata.ingestion.api.models import Either
 from metadata.ingestion.api.steps import InvalidSourceException
 from metadata.ingestion.lineage.models import ConnectionTypeDialectMapper, Dialect
 from metadata.ingestion.lineage.parser import LineageParser
+from metadata.ingestion.lineage.sql_lineage import get_column_fqn
 from metadata.ingestion.ometa.ometa_api import OpenMetadata
 from metadata.ingestion.source.dashboard.dashboard_service import (
     LINEAGE_MAP,
@@ -233,6 +238,99 @@ def _describe_data_sets(self, dataset_id, dashboard_details: DashboardDetail) ->
             logger.info(f"Cannot parse lineage from the dashboard: {dashboard_details.Name} to dataset due to: {err}")
             return dataset_id, []
 
+    def _build_column_lineage_from_parser(
+        self,
+        lineage_parser: LineageParser,
+        from_entity: Table,
+        data_model_entity: DashboardDataModel,
+    ) -> list[ColumnLineage]:
+        """
+        Build column-level lineage using SQL parser alias mappings.
+
+        When a QuickSight CustomSql query uses column aliases
+        (e.g. ``SELECT id AS relation_id``), name-based matching fails
+        because the alias name is matched against upstream columns instead
+        of tracing back through the SQL expression.
+
+        This method uses :class:`LineageParser` column mappings to resolve
+        the true source column (``id``) from the alias (``relation_id``),
+        and filters by ``src_col._parent`` to avoid multi-table column
+        name collisions.
+
+        Falls back to :meth:`_get_column_lineage` when the parser returns
+        no column lineage (e.g. SQL too complex, parsing failed, or no
+        aliases present).
+
+        Issue #26670.
+        """
+        column_lineage: list[ColumnLineage] = []
+
+        for col_pair in lineage_parser.column_lineage or []:
+            # Guard: parser may return single-element tuples in edge cases
+            if len(col_pair) < 2:
+                continue
+
+            src_col = col_pair[0]
+            tgt_col = col_pair[-1]
+
+            parent = getattr(src_col, "_parent", None)
+            # _parent may be a single Table, an iterable of Tables, or an
+            # empty iterable when the parser could not infer the source table.
+            # Treat empty iterables the same as missing parent info.
+            if parent:
+                parents = list(parent) if hasattr(parent, "__iter__") and not isinstance(parent, str) else [parent]
+            else:
+                parents = []
+
+            if parents:
+                entity_table = from_entity.name.root.lower()
+                # Accept the pair only when at least one parent table
+                # matches the current upstream entity being processed.
+                if not any(str(p).replace("<default>.", "").split(".")[-1].lower() == entity_table for p in parents):
+                    continue
+            else:
+                # _parent is missing or empty — parser could not determine source
+                # table. Log for visibility but allow the pair through;
+                # get_column_fqn provides a secondary guard (column must
+                # exist in entity).
+                logger.debug(
+                    "No parent table info for column %s; skipping parent-table filter",
+                    src_col.raw_name,
+                )
+
+            # raw_name may be fully-qualified (e.g. 'schema.table.col')
+            # Extract just the column name portion.
+            src_col_name = src_col.raw_name.split(".")[-1]
+            tgt_col_name = tgt_col.raw_name.split(".")[-1]
+
+            try:
+                from_col_fqn = get_column_fqn(table_entity=from_entity, column=src_col_name)
+                to_col_fqn = self._get_data_model_column_fqn(
+                    data_model_entity=data_model_entity,
+                    column=tgt_col_name,
+                )
+                if from_col_fqn and to_col_fqn:
+                    column_lineage.append(
+                        ColumnLineage(
+                            fromColumns=[from_col_fqn],
+                            toColumn=to_col_fqn,
+                        )
+                    )
+            except Exception as exc:  # pylint: disable=broad-except
+                logger.debug(f"Failed to build column lineage for {src_col_name} -> {tgt_col_name}: {exc}")
+                logger.debug(traceback.format_exc())
+
+        # Only fall back to name-based matching when the parser found
+        # NO column lineage globally (parse failure, too complex, no aliases).
+        # If the parser DID produce lineage but none matched this specific
+        # from_entity (multi-table query), return an empty list rather than
+        # manufacturing incorrect cross-table lineage.
+        if not column_lineage and not lineage_parser.column_lineage:
+            columns = [col.name.root for col in data_model_entity.columns]
+            return self._get_column_lineage(from_entity, data_model_entity, columns)
+
+        return column_lineage
+
     def _yield_lineage_from_query(
         self,
         data_model_entity,
@@ -308,8 +406,9 @@ def _yield_lineage_from_query(
                     )
                     for from_entity in from_entities or []:
                         if from_entity is not None and data_model_entity is not None:
-                            columns = [col.name.root for col in data_model_entity.columns]
-                            column_lineage = self._get_column_lineage(from_entity, data_model_entity, columns)
+                            column_lineage = self._build_column_lineage_from_parser(
+                                lineage_parser, from_entity, data_model_entity
+                            )
                             lineage_details.columnsLineage = column_lineage
                             yield Either(
                                 right=AddLineageRequest(
diff --git a/ingestion/tests/unit/topology/dashboard/test_quicksight.py b/ingestion/tests/unit/topology/dashboard/test_quicksight.py
index ecfed49896cc..776845590f7c 100644
--- a/ingestion/tests/unit/topology/dashboard/test_quicksight.py
+++ b/ingestion/tests/unit/topology/dashboard/test_quicksight.py
@@ -364,6 +364,7 @@ def describe_data_set_side_effect(**kwargs):
         col_names_b = {col.name.root for col in dm_b.columns}
         assert col_names_b == {"email", "created_at"}
 
+    @pytest.mark.order(9)
     def test_chart_source_state_populated(self):
         """Verify register_record_chart populates chart_source_state after yield_dashboard_chart."""
         dashboard_details = DashboardDetail(**{**MOCK_DASHBOARD_DETAILS, "Version": mock_data["Version"]})
@@ -372,3 +373,228 @@ def test_chart_source_state_populated(self):
         assert len(self.quicksight.chart_source_state) == len(mock_data["Version"]["Sheets"])
         for fqn in self.quicksight.chart_source_state:
             assert "quicksight_source_test" in fqn
+
+    @pytest.mark.order(10)
+    def test_build_column_lineage_from_parser_resolves_alias(self):
+        """
+        When CustomSql uses SELECT src_col AS alias_col,
+        _build_column_lineage_from_parser must map src_col (source)
+        to alias_col (data model column) — not match by name.
+        Issue #26670.
+        """
+        src_col = MagicMock()
+        src_col.raw_name = "id"
+        src_col._parent = None  # No parent — single-table query
+
+        tgt_col = MagicMock()
+        tgt_col.raw_name = "relation_id"
+
+        mock_parser = MagicMock()
+        mock_parser.column_lineage = [(src_col, tgt_col)]
+
+        src_fqn = "postgres.public.relation_table.id"
+        alias_fqn = "quicksight_service.dataset.relation_id"
+
+        mock_from_entity = MagicMock()
+        mock_from_entity.name.root = "relation_table"
+        mock_data_model = MagicMock()
+
+        with (
+            patch(
+                "metadata.ingestion.source.dashboard.quicksight.metadata.get_column_fqn",
+                return_value=src_fqn,
+            ) as mock_get_col_fqn,
+            patch.object(
+                self.quicksight,
+                "_get_data_model_column_fqn",
+                return_value=alias_fqn,
+            ) as mock_get_dm_col_fqn,
+        ):
+            result = self.quicksight._build_column_lineage_from_parser(mock_parser, mock_from_entity, mock_data_model)
+
+        mock_get_col_fqn.assert_called_once_with(table_entity=mock_from_entity, column="id")
+        mock_get_dm_col_fqn.assert_called_once_with(data_model_entity=mock_data_model, column="relation_id")
+        assert len(result) == 1
+        assert result[0].fromColumns[0].root == src_fqn
+        assert result[0].toColumn.root == alias_fqn
+
+    @pytest.mark.order(11)
+    def test_build_column_lineage_from_parser_multi_table_filters_correctly(self):
+        """
+        When CustomSql joins multiple tables with shared column names
+        (e.g. t1.id and t2.id), _build_column_lineage_from_parser must
+        only emit lineage for columns belonging to from_entity — not
+        columns from other tables with the same name.
+        Issue #26670.
+        """
+        # Column from the correct upstream table
+        src_col_correct = MagicMock()
+        src_col_correct.raw_name = "id"
+        src_col_correct._parent = type("_FakeTable", (), {"__str__": lambda self: "relation_table"})()
+
+        tgt_col_correct = MagicMock()
+        tgt_col_correct.raw_name = "relation_id"
+
+        # Column from a DIFFERENT table with same name 'id'
+        src_col_wrong = MagicMock()
+        src_col_wrong.raw_name = "id"
+        src_col_wrong._parent = type("_FakeTable", (), {"__str__": lambda self: "other_table"})()
+
+        tgt_col_wrong = MagicMock()
+        tgt_col_wrong.raw_name = "other_relation_id"
+
+        mock_parser = MagicMock()
+        mock_parser.column_lineage = [
+            (src_col_correct, tgt_col_correct),
+            (src_col_wrong, tgt_col_wrong),
+        ]
+
+        src_fqn = "postgres.public.relation_table.id"
+        alias_fqn = "quicksight_service.dataset.relation_id"
+
+        mock_from_entity = MagicMock()
+        mock_from_entity.name.root = "relation_table"
+        mock_data_model = MagicMock()
+
+        with (
+            patch(
+                "metadata.ingestion.source.dashboard.quicksight.metadata.get_column_fqn",
+                return_value=src_fqn,
+            ),
+            patch.object(
+                self.quicksight,
+                "_get_data_model_column_fqn",
+                return_value=alias_fqn,
+            ),
+        ):
+            result = self.quicksight._build_column_lineage_from_parser(mock_parser, mock_from_entity, mock_data_model)
+
+        # Only 1 result — the wrong table's column must be filtered out
+        assert len(result) == 1
+        assert result[0].fromColumns[0].root == src_fqn
+        assert result[0].toColumn.root == alias_fqn
+
+    @pytest.mark.order(12)
+    def test_build_column_lineage_no_fallback_when_parser_has_global_lineage(self):
+        """
+        Regression test for the multi-table fallback bug (Issue #26670).
+
+        When lineage_parser.column_lineage is non-empty (parser succeeded)
+        but none of the pairs match from_entity (because they belong to a
+        different upstream table in a multi-table JOIN), the method must
+        return an empty list and must NOT call _get_column_lineage (the
+        name-based fallback). Calling the fallback here would manufacture
+        incorrect cross-table column lineage.
+        """
+        # Parser found lineage for a DIFFERENT table, not our from_entity
+        other_src_col = MagicMock()
+        other_src_col.raw_name = "user_id"
+        other_src_col._parent = type("_FakeTable", (), {"__str__": lambda self: "users_table"})()
+
+        other_tgt_col = MagicMock()
+        other_tgt_col.raw_name = "uid"
+
+        mock_parser = MagicMock()
+        # Parser globally found lineage — but only for 'users_table'
+        mock_parser.column_lineage = [(other_src_col, other_tgt_col)]
+
+        mock_from_entity = MagicMock()
+        # Our from_entity is 'orders_table' — no parser pairs match it
+        mock_from_entity.name.root = "orders_table"
+        mock_data_model = MagicMock()
+
+        with patch.object(
+            self.quicksight,
+            "_get_column_lineage",
+        ) as mock_fallback:
+            result = self.quicksight._build_column_lineage_from_parser(mock_parser, mock_from_entity, mock_data_model)
+
+        # Must NOT have called the name-based fallback
+        mock_fallback.assert_not_called()
+        # Must return an empty list — no manufactured lineage
+        assert result == []
+
+    @pytest.mark.order(13)
+    def test_build_column_lineage_from_parser_iterable_parent(self):
+        """
+        When src_col._parent is an iterable of parent tables (as some
+        parser outputs produce), _build_column_lineage_from_parser must
+        correctly match against from_entity when any parent matches.
+        Issue #26670.
+        """
+        # Parent is an iterable (list) of Table objects
+        parent_table_mock = MagicMock()
+        parent_table_mock.__str__ = MagicMock(return_value="relation_table")
+
+        src_col = MagicMock()
+        src_col.raw_name = "id"
+        # _parent is a list — simulates iterable parser output
+        src_col._parent = [parent_table_mock]
+
+        tgt_col = MagicMock()
+        tgt_col.raw_name = "relation_id"
+
+        mock_parser = MagicMock()
+        mock_parser.column_lineage = [(src_col, tgt_col)]
+
+        src_fqn = "postgres.public.relation_table.id"
+        alias_fqn = "quicksight_service.dataset.relation_id"
+
+        mock_from_entity = MagicMock()
+        mock_from_entity.name.root = "relation_table"
+        mock_data_model = MagicMock()
+
+        with (
+            patch(
+                "metadata.ingestion.source.dashboard.quicksight.metadata.get_column_fqn",
+                return_value=src_fqn,
+            ),
+            patch.object(
+                self.quicksight,
+                "_get_data_model_column_fqn",
+                return_value=alias_fqn,
+            ),
+        ):
+            result = self.quicksight._build_column_lineage_from_parser(
+                mock_parser,
+                mock_from_entity,
+                mock_data_model,
+            )
+
+        assert len(result) == 1
+        assert result[0].fromColumns[0].root == src_fqn
+        assert result[0].toColumn.root == alias_fqn
+
+    @pytest.mark.order(14)
+    def test_build_column_lineage_from_parser_falls_back_when_empty(self):
+        """
+        When lineage_parser.column_lineage is empty (parser failed or
+        no aliases), _build_column_lineage_from_parser must fall back
+        to name-based matching via _get_column_lineage.
+        Issue #26670.
+        """
+        mock_parser = MagicMock()
+        mock_parser.column_lineage = []
+
+        fallback_lineage = [MagicMock()]
+        mock_from_entity = MagicMock()
+        mock_from_entity.name.root = "relation_table"
+
+        # Build mock columns properly — avoid MagicMock name kwarg trap
+        mock_col = MagicMock()
+        mock_col.name = MagicMock()
+        mock_col.name.root = "col_a"
+
+        mock_data_model = MagicMock()
+        mock_data_model.columns = [mock_col]
+
+        with patch.object(
+            self.quicksight,
+            "_get_column_lineage",
+            return_value=fallback_lineage,
+        ) as mock_get_col_lineage:
+            result = self.quicksight._build_column_lineage_from_parser(mock_parser, mock_from_entity, mock_data_model)
+
+        # Verify fallback was called with correct column names
+        mock_get_col_lineage.assert_called_once_with(mock_from_entity, mock_data_model, ["col_a"])
+        assert result is fallback_lineage