diff --git a/src/elements/msubsup.rs b/src/elements/msubsup.rs
index e29f124..e07c9ce 100644
--- a/src/elements/msubsup.rs
+++ b/src/elements/msubsup.rs
@@ -6,7 +6,7 @@ use crate::{
     Element, Elements,
 };
 
-use super::IntoElements;
+use super::{grouping::Row, IntoElements};
 
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 enum SubSupInner {
@@ -72,6 +72,12 @@ pub struct SubSupBuilder<T1, T2> {
 impl<T1, T2> SubSupBuilder<T1, T2> {
     /// Set the base of the [`SubSup`] element.
     pub fn base(self, base: impl IntoElements) -> SubSupBuilder<Init, T2> {
+        let mut base = base.into_elements();
+
+        if base.len() > 1 {
+            base = Row::from(base).into_elements();
+        }
+
         SubSupBuilder {
             base: Some(base.into_elements()),
             sub: self.sub,
@@ -83,6 +89,12 @@ impl<T1, T2> SubSupBuilder<T1, T2> {
 
     /// Set the subscript of the [`SubSup`] element.
     pub fn subscript(self, sub: impl IntoElements) -> SubSupBuilder<T1, Init> {
+        let mut sub = sub.into_elements();
+
+        if sub.len() > 1 {
+            sub = Row::from(sub).into_elements();
+        }
+
         SubSupBuilder {
             base: self.base,
             sub: Some(sub.into_elements()),
@@ -94,6 +106,12 @@ impl<T1, T2> SubSupBuilder<T1, T2> {
 
     /// Set the superscript of the [`SubSup`] element.
     pub fn supscript(self, sup: impl IntoElements) -> SubSupBuilder<T1, Init> {
+        let mut sup = sup.into_elements();
+
+        if sup.len() > 1 {
+            sup = Row::from(sup).into_elements();
+        }
+
         SubSupBuilder {
             base: self.base,
             sub: self.sub,
@@ -132,8 +150,10 @@ impl SubSupBuilder<Init, Init> {
             }
         };
 
+        let base = self.base.expect("Base is guaranteed to be init.");
+
         SubSup {
-            base: self.base.expect("Base is guaranteed to be init."),
+            base,
             inner,
             attributes: self.attr,
         }
diff --git a/src/elements/munderover.rs b/src/elements/munderover.rs
index 3730d5f..7da3e9b 100644
--- a/src/elements/munderover.rs
+++ b/src/elements/munderover.rs
@@ -99,6 +99,12 @@ pub struct UnderOverBuilder<T1, T2> {
 impl<T1, T2> UnderOverBuilder<T1, T2> {
     /// Set the base expression of the [`UnderOver`] element.
     pub fn expr(self, expr: impl IntoElements) -> UnderOverBuilder<Init, T2> {
+        let mut expr = expr.into_elements();
+
+        if expr.len() > 1 {
+            expr = Row::from(expr).into_elements();
+        }
+
         UnderOverBuilder {
             expr: Some(expr.into_elements()),
             under: self.under,
@@ -111,6 +117,12 @@ impl<T1, T2> UnderOverBuilder<T1, T2> {
 
     /// Set the under script of the [`UnderOver`] element.
     pub fn over(self, over: impl IntoElements) -> UnderOverBuilder<T1, Init> {
+        let mut over = over.into_elements();
+
+        if over.len() > 1 {
+            over = Row::from(over).into_elements();
+        }
+
         UnderOverBuilder {
             expr: self.expr,
             under: self.under,
@@ -122,6 +134,12 @@ impl<T1, T2> UnderOverBuilder<T1, T2> {
 
     /// Set the over script of the [`UnderOver`] element.
     pub fn under(self, under: impl IntoElements) -> UnderOverBuilder<T1, Init> {
+        let mut under = under.into_elements();
+
+        if under.len() > 1 {
+            under = Row::from(under).into_elements();
+        }
+
         UnderOverBuilder {
             expr: self.expr,
             under: Some(under.into_elements()),
@@ -160,11 +178,7 @@ impl UnderOverBuilder<Init, Init> {
             }
         };
 
-        let mut expr = self.expr.expect("Expr is guaranteed to be init.");
-
-        if expr.len() > 1 {
-            expr = Row::from(expr).into_elements();
-        }
+        let expr = self.expr.expect("Expr is guaranteed to be init.");
 
         UnderOver {
             expr,
diff --git a/tests/scripted/mod.rs b/tests/scripted/mod.rs
index 8608d0d..d657d89 100644
--- a/tests/scripted/mod.rs
+++ b/tests/scripted/mod.rs
@@ -16,6 +16,28 @@ fn subsup() {
     crate::snap_test!(out, name: "subsup_subsup");
 }
 
+#[test]
+fn subsup_many() {
+    let sub = alemat::children![
+        Operator::lparens(),
+        Ident::from("n"),
+        Operator::eq(),
+        Num::from(0),
+        Operator::rparens(),
+    ];
+
+    let sup = alemat::children![Ident::from("k"), Operator::plus(), Num::from(1)];
+
+    let out = MathMl::with_content(alemat::children![SubSup::builder()
+        .base(Operator::integral())
+        .subscript(sub)
+        .supscript(sup)
+        .build()])
+    .render();
+
+    crate::snap_test!(out, name: "subsup_many");
+}
+
 #[test]
 fn subsup_integral() {
     let out = MathMl::with_content(alemat::children![
@@ -66,6 +88,28 @@ fn underover() {
     crate::snap_test!(out, name: "underover_underover");
 }
 
+#[test]
+fn underover_many() {
+    let under = alemat::children![
+        Operator::lparens(),
+        Ident::from("n"),
+        Operator::eq(),
+        Num::from(0),
+        Operator::rparens(),
+    ];
+
+    let over = alemat::children![Ident::from("k"), Operator::plus(), Num::from(1)];
+
+    let out = MathMl::with_content(alemat::children![UnderOver::builder()
+        .expr(Operator::sum())
+        .under(under)
+        .over(over)
+        .build()])
+    .render();
+
+    crate::snap_test!(out, name: "underover_many");
+}
+
 #[test]
 fn underover_integral() {
     let out = MathMl::with_content(alemat::children![
diff --git a/tests/snapshots/subsup_many.snap b/tests/snapshots/subsup_many.snap
new file mode 100644
index 0000000..4ccefbc
--- /dev/null
+++ b/tests/snapshots/subsup_many.snap
@@ -0,0 +1,40 @@
+---
+source: tests/scripted/mod.rs
+expression: input
+---
+<math>
+  <msubsup>
+    <mo>
+      ∫
+    </mo>
+    <mrow>
+      <mo>
+        (
+      </mo>
+      <mi>
+        n
+      </mi>
+      <mo>
+        =
+      </mo>
+      <mn>
+        0
+      </mn>
+      <mo>
+        )
+      </mo>
+    </mrow>
+    <mrow>
+      <mi>
+        k
+      </mi>
+      <mo>
+        +
+      </mo>
+      <mn>
+        1
+      </mn>
+    </mrow>
+  </msubsup>
+</math>
+
diff --git a/tests/snapshots/underover_many.snap b/tests/snapshots/underover_many.snap
new file mode 100644
index 0000000..438fdf0
--- /dev/null
+++ b/tests/snapshots/underover_many.snap
@@ -0,0 +1,40 @@
+---
+source: tests/scripted/mod.rs
+expression: input
+---
+<math>
+  <munderover>
+    <mo>
+      ∑
+    </mo>
+    <mrow>
+      <mo>
+        (
+      </mo>
+      <mi>
+        n
+      </mi>
+      <mo>
+        =
+      </mo>
+      <mn>
+        0
+      </mn>
+      <mo>
+        )
+      </mo>
+    </mrow>
+    <mrow>
+      <mi>
+        k
+      </mi>
+      <mo>
+        +
+      </mo>
+      <mn>
+        1
+      </mn>
+    </mrow>
+  </munderover>
+</math>
+