diff --git a/pkg/sql/catalog/post_deserialization_changes.go b/pkg/sql/catalog/post_deserialization_changes.go
index e6369550d307..ff896a30483a 100644
--- a/pkg/sql/catalog/post_deserialization_changes.go
+++ b/pkg/sql/catalog/post_deserialization_changes.go
@@ -98,4 +98,8 @@ const (
 	// SetCreateAsOfTimeUsingModTime indicates that a table's CreateAsOfTime field
 	// was unset and the ModificationTime value was assigned to it.
 	SetCreateAsOfTimeUsingModTime
+
+	// FixSecondaryIndexEncodingType indicates that a secondary index had its
+	// encoding type fixed, so it is not incorrectly marked as a primary index.
+	FixSecondaryIndexEncodingType
 )
diff --git a/pkg/sql/catalog/tabledesc/BUILD.bazel b/pkg/sql/catalog/tabledesc/BUILD.bazel
index 841155855294..353b9f9c9969 100644
--- a/pkg/sql/catalog/tabledesc/BUILD.bazel
+++ b/pkg/sql/catalog/tabledesc/BUILD.bazel
@@ -104,6 +104,7 @@ go_test(
         "//pkg/sql/catalog/internal/validate",
         "//pkg/sql/catalog/nstree",
         "//pkg/sql/privilege",
+        "//pkg/sql/schemachanger/scpb",
         "//pkg/sql/sem/catconstants",
         "//pkg/sql/sem/catid",
         "//pkg/sql/types",
diff --git a/pkg/sql/catalog/tabledesc/structured_test.go b/pkg/sql/catalog/tabledesc/structured_test.go
index 80cf89414d1a..c3e6dde530f3 100644
--- a/pkg/sql/catalog/tabledesc/structured_test.go
+++ b/pkg/sql/catalog/tabledesc/structured_test.go
@@ -28,6 +28,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/desctestutils"
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/internal/validate"
 	. "github.com/cockroachdb/cockroach/pkg/sql/catalog/tabledesc"
+	"github.com/cockroachdb/cockroach/pkg/sql/schemachanger/scpb"
 	"github.com/cockroachdb/cockroach/pkg/sql/types"
 	"github.com/cockroachdb/cockroach/pkg/testutils/serverutils"
 	"github.com/cockroachdb/cockroach/pkg/testutils/sqlutils"
@@ -681,6 +682,111 @@ func TestUnvalidateConstraints(t *testing.T) {
 	}
 }
 
+func TestMaybeFixSecondaryIndexEncodingType(t *testing.T) {
+	tests := []struct {
+		desc       descpb.TableDescriptor
+		expUpgrade bool
+		verify     func(*testing.T, int, catalog.TableDescriptor) // nil means no extra verification.
+	}{
+		{ // 1
+			desc: descpb.TableDescriptor{
+				ID:            2,
+				ParentID:      1,
+				Name:          "foo",
+				FormatVersion: descpb.InterleavedFormatVersion,
+				Columns: []descpb.ColumnDescriptor{
+					{ID: 1, Name: "bar"},
+					{ID: 2, Name: "baz"},
+				},
+				Families: []descpb.ColumnFamilyDescriptor{
+					{ID: 0, Name: "primary", ColumnIDs: []descpb.ColumnID{1, 2}, ColumnNames: []string{"bar", "baz"}},
+				},
+				Privileges: catpb.NewBasePrivilegeDescriptor(username.RootUserName()),
+				PrimaryIndex: descpb.IndexDescriptor{ID: 1, Name: "primary",
+					KeyColumnIDs:        []descpb.ColumnID{1, 2},
+					KeyColumnNames:      []string{"bar", "baz"},
+					KeyColumnDirections: []catpb.IndexColumn_Direction{catpb.IndexColumn_ASC, catpb.IndexColumn_ASC},
+					EncodingType:        descpb.PrimaryIndexEncoding,
+					Version:             descpb.LatestIndexDescriptorVersion,
+					ConstraintID:        1,
+				},
+				Indexes: []descpb.IndexDescriptor{{
+					ID:                  2,
+					Name:                "secondary",
+					KeyColumnIDs:        []descpb.ColumnID{2},
+					KeyColumnNames:      []string{"baz"},
+					KeyColumnDirections: []catpb.IndexColumn_Direction{catpb.IndexColumn_ASC},
+					EncodingType:        descpb.PrimaryIndexEncoding,
+				}},
+				NextColumnID:     3,
+				NextFamilyID:     1,
+				NextIndexID:      3,
+				NextConstraintID: 2,
+			},
+			expUpgrade: true,
+			verify: func(t *testing.T, _ int, newDesc catalog.TableDescriptor) {
+				require.Equal(t, descpb.SecondaryIndexEncoding, newDesc.TableDesc().Indexes[0].EncodingType)
+			},
+		},
+		{ // 2
+			desc: descpb.TableDescriptor{
+				ID:            2,
+				ParentID:      1,
+				Name:          "foo",
+				FormatVersion: descpb.InterleavedFormatVersion,
+				Columns: []descpb.ColumnDescriptor{
+					{ID: 1, Name: "bar"},
+					{ID: 2, Name: "baz"},
+				},
+				Families: []descpb.ColumnFamilyDescriptor{
+					{ID: 0, Name: "primary", ColumnIDs: []descpb.ColumnID{1, 2}, ColumnNames: []string{"bar", "baz"}},
+				},
+				Privileges: catpb.NewBasePrivilegeDescriptor(username.RootUserName()),
+				PrimaryIndex: descpb.IndexDescriptor{ID: 1, Name: "primary",
+					KeyColumnIDs:        []descpb.ColumnID{1, 2},
+					KeyColumnNames:      []string{"bar", "baz"},
+					KeyColumnDirections: []catpb.IndexColumn_Direction{catpb.IndexColumn_ASC, catpb.IndexColumn_ASC},
+					EncodingType:        descpb.PrimaryIndexEncoding,
+					Version:             descpb.LatestIndexDescriptorVersion,
+					ConstraintID:        1,
+				},
+				Indexes: []descpb.IndexDescriptor{{
+					ID:                  2,
+					Name:                "secondary",
+					KeyColumnIDs:        []descpb.ColumnID{2},
+					KeyColumnNames:      []string{"baz"},
+					KeyColumnDirections: []catpb.IndexColumn_Direction{catpb.IndexColumn_ASC},
+					EncodingType:        descpb.PrimaryIndexEncoding,
+				}},
+				DeclarativeSchemaChangerState: &scpb.DescriptorState{
+					JobID: catpb.JobID(1),
+				},
+				NextColumnID:     3,
+				NextFamilyID:     1,
+				NextIndexID:      3,
+				NextConstraintID: 2,
+			},
+			expUpgrade: false,
+		},
+	}
+	for i, test := range tests {
+		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
+			b := NewBuilder(&test.desc)
+			require.NoError(t, b.RunPostDeserializationChanges())
+			desc := b.BuildImmutableTable()
+			changes, err := GetPostDeserializationChanges(desc)
+			require.NoError(t, err)
+			upgraded := changes.Contains(catalog.FixSecondaryIndexEncodingType)
+			if upgraded != test.expUpgrade {
+				t.Fatalf("%d: expected upgraded=%t, but got upgraded=%t", i, test.expUpgrade, upgraded)
+			}
+			if test.verify != nil {
+				test.verify(t, i, desc)
+			}
+		})
+	}
+}
+
 func TestKeysPerRow(t *testing.T) {
 	defer leaktest.AfterTest(t)()
 
diff --git a/pkg/sql/catalog/tabledesc/table_desc_builder.go b/pkg/sql/catalog/tabledesc/table_desc_builder.go
index 20bf13a24914..06e750f3633f 100644
--- a/pkg/sql/catalog/tabledesc/table_desc_builder.go
+++ b/pkg/sql/catalog/tabledesc/table_desc_builder.go
@@ -304,6 +304,7 @@ func maybeFillInDescriptor(
 	set(catalog.UpgradedPrivileges, fixedPrivileges)
 	set(catalog.RemovedDuplicateIDsInRefs, maybeRemoveDuplicateIDsInRefs(desc))
 	set(catalog.AddedConstraintIDs, maybeAddConstraintIDs(desc))
+	set(catalog.FixSecondaryIndexEncodingType, maybeFixSecondaryIndexEncodingType(desc))
 	return changes, nil
 }
 
@@ -831,6 +832,21 @@ func maybeAddConstraintIDs(desc *descpb.TableDescriptor) (hasChanged bool) {
 	return desc.NextConstraintID != initialConstraintID
 }
 
+func maybeFixSecondaryIndexEncodingType(desc *descpb.TableDescriptor) (hasChanged bool) {
+	if desc.DeclarativeSchemaChangerState != nil || len(desc.Mutations) > 0 {
+		// Don't try to fix the encoding type if a schema change is in progress.
+		return false
+	}
+	for i := range desc.Indexes {
+		idx := &desc.Indexes[i]
+		if idx.EncodingType != descpb.SecondaryIndexEncoding {
+			idx.EncodingType = descpb.SecondaryIndexEncoding
+			hasChanged = true
+		}
+	}
+	return hasChanged
+}
+
 // maybeSetCreateAsOfTime ensures that the CreateAsOfTime field is set.
 //
 // CreateAsOfTime is used for CREATE TABLE ... AS ... and was introduced in