diff --git a/crates/typst-library/src/layout/par.rs b/crates/typst-library/src/layout/par.rs
index 271d9467b..9e5d4a97e 100644
--- a/crates/typst-library/src/layout/par.rs
+++ b/crates/typst-library/src/layout/par.rs
@@ -908,6 +908,7 @@ fn linebreak_optimized<'a>(vt: &Vt, p: &'a Preparation<'a>, width: Abs) -> Vec<L
 
     // Cost parameters.
     const HYPH_COST: Cost = 0.5;
+    const RUNT_COST: Cost = 0.5;
     const CONSECUTIVE_DASH_COST: Cost = 300.0;
     const MAX_COST: Cost = 1_000_000.0;
     const MIN_RATIO: f64 = -1.0;
@@ -984,6 +985,11 @@ fn linebreak_optimized<'a>(vt: &Vt, p: &'a Preparation<'a>, width: Abs) -> Vec<L
                 ratio.powi(3).abs()
             };
 
+            // Penalize runts.
+            if k == i + 1 && eof {
+                cost += RUNT_COST;
+            }
+
             // Penalize hyphens.
             if hyphen {
                 cost += HYPH_COST;
diff --git a/tests/ref/layout/par-justify.png b/tests/ref/layout/par-justify.png
index 9f92034f9..fd25c5b7e 100644
Binary files a/tests/ref/layout/par-justify.png and b/tests/ref/layout/par-justify.png differ
diff --git a/tests/typ/layout/par-justify.typ b/tests/typ/layout/par-justify.typ
index 8d985cbf2..2e5b48063 100644
--- a/tests/typ/layout/par-justify.typ
+++ b/tests/typ/layout/par-justify.typ
@@ -31,3 +31,12 @@ D E F #linebreak(justify: true)
 #set page(width: 155pt)
 #set par(justify: true)
 This text can be fitted in one line.
+
+---
+// Test that runts are avoided when it's not too costly to do so.
+#set page(width: 124pt)
+#set par(justify: true)
+#for i in range(0, 20) {
+	"a b c "
+}
+#"d"