diff --git a/src/main/java/org/apache/commons/collections4/list/TreeList.java b/src/main/java/org/apache/commons/collections4/list/TreeList.java
index bfa1d9c06..3acc7d2ab 100644
--- a/src/main/java/org/apache/commons/collections4/list/TreeList.java
+++ b/src/main/java/org/apache/commons/collections4/list/TreeList.java
@@ -30,7 +30,7 @@ import org.apache.commons.collections4.CollectionUtils;
 import org.apache.commons.collections4.OrderedIterator;
 
 /**
- * A {@code List} implementation that is optimised for fast insertions and
+ * A {@code List} implementation that is optimized for fast insertions and
  * removals at any index in the list.
  * <p>
  * This list implementation utilises a tree structure internally to ensure that
diff --git a/src/main/java/org/apache/commons/collections4/list/package-info.java b/src/main/java/org/apache/commons/collections4/list/package-info.java
index becf550bc..d76d3b16e 100644
--- a/src/main/java/org/apache/commons/collections4/list/package-info.java
+++ b/src/main/java/org/apache/commons/collections4/list/package-info.java
@@ -19,7 +19,7 @@
  * <p>
  * The following implementations are provided in the package:
  * <ul>
- *   <li>TreeList - a list that is optimised for insertions and removals at any index in the list</li>
+ *   <li>TreeList - a list that is optimized for insertions and removals at any index in the list</li>
  *   <li>CursorableLinkedList - a list that can be modified while the listIterator (cursor) is being used</li>
  *   <li>NodeCachingLinkedList - a linked list that caches the storage nodes for a performance gain</li>
  * </ul>
diff --git a/src/main/java/org/apache/commons/collections4/map/AbstractInputCheckedMapDecorator.java b/src/main/java/org/apache/commons/collections4/map/AbstractInputCheckedMapDecorator.java
index 3a76ecbbb..34fdbc59a 100644
--- a/src/main/java/org/apache/commons/collections4/map/AbstractInputCheckedMapDecorator.java
+++ b/src/main/java/org/apache/commons/collections4/map/AbstractInputCheckedMapDecorator.java
@@ -86,7 +86,7 @@ abstract class AbstractInputCheckedMapDecorator<K, V>
      * Hook method called to determine if {@code checkSetValue} has any effect.
      * <p>
      * An implementation should return false if the {@code checkSetValue} method
-     * has no effect as this optimises the implementation.
+     * has no effect as this optimizes the implementation.
      * <p>
      * This implementation returns {@code true}.
      *
diff --git a/src/test/java/org/apache/commons/collections4/list/NodeCachingLinkedListTest.java b/src/test/java/org/apache/commons/collections4/list/NodeCachingLinkedListTest.java
index 5b58dec1d..1d775274a 100644
--- a/src/test/java/org/apache/commons/collections4/list/NodeCachingLinkedListTest.java
+++ b/src/test/java/org/apache/commons/collections4/list/NodeCachingLinkedListTest.java
@@ -22,7 +22,7 @@ import java.util.LinkedList;
 import org.junit.jupiter.api.Test;
 
 /**
- * Test class for NodeCachingLinkedList, a performance optimised LinkedList.
+ * Test class for NodeCachingLinkedList, a performance optimized LinkedList.
  */
 public class NodeCachingLinkedListTest<E> extends AbstractLinkedListTest<E> {