Index: lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/GradebookService.java
===================================================================
diff -u -rb41a65a8bc95cd6c8b5e3d22ecdf1a352ad6bcc0 -r7ad79c50d0bc5a1021cae22a121c1123f3943db3
--- lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/GradebookService.java	(.../GradebookService.java)	(revision b41a65a8bc95cd6c8b5e3d22ecdf1a352ad6bcc0)
+++ lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/GradebookService.java	(.../GradebookService.java)	(revision 7ad79c50d0bc5a1021cae22a121c1123f3943db3)
@@ -26,6 +26,7 @@
 import java.text.DateFormat;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -53,6 +54,7 @@
 import org.lamsfoundation.lams.gradebook.util.GBGridView;
 import org.lamsfoundation.lams.gradebook.util.GradebookConstants;
 import org.lamsfoundation.lams.gradebook.util.LessonComparator;
+import org.lamsfoundation.lams.gradebook.util.UserComparator;
 import org.lamsfoundation.lams.learningdesign.Activity;
 import org.lamsfoundation.lams.learningdesign.Group;
 import org.lamsfoundation.lams.learningdesign.Grouping;
@@ -296,6 +298,8 @@
 	    //size will be 0 in case of excel export 
 	    if (size == 0) {
 		learners =  new LinkedList<User>(lesson.getAllLearners());
+		Collections.sort(learners, new UserComparator());
+		
 		userToLearnerProgressMap = getUserToLearnerProgressMap(lesson, null);
 		userToGradebookUserLessonMap = getUserToGradebookUserLessonMap(lesson, null);
 		
@@ -619,10 +623,11 @@
 
 	HashMap<ToolActivity, List<GBUserGridRowDTO>> activityToUserDTOMap = new HashMap<ToolActivity, List<GBUserGridRowDTO>>();
 
-	Set<User> learners = lesson.getAllLearners();
-	if (learners == null) {
-	    learners = new TreeSet<User>();
+	Set<User> learners = new TreeSet<User>(new UserComparator());
+	if (lesson.getAllLearners() != null) {
+	    learners.addAll(lesson.getAllLearners());
 	}
+	
 	Map<Integer, LearnerProgress> userToLearnerProgressMap = getUserToLearnerProgressMap(lesson, null);
 	Set<ToolActivity> activities = getLessonActivities(lesson);
 
@@ -771,9 +776,9 @@
 
 	// -------------------- process Learner View page --------------------------------
 
-	Set<User> learners = lesson.getAllLearners();
-	if (learners == null) {
-	    learners = new TreeSet<User>();
+	Set<User> learners = new TreeSet<User>(new UserComparator());
+	if (lesson.getAllLearners() != null) {
+	    learners.addAll(lesson.getAllLearners());
 	}
 
 	rowList = new LinkedList<ExcelCell[]>();
@@ -872,7 +877,7 @@
 	    rowList.add(headerRow);
 
 	    // collect users from all lessons
-	    Set<User> allLearners = new LinkedHashSet<User>();
+	    LinkedHashSet<User> allLearners = new LinkedHashSet<User>();
 	    List<Long> lessonIds = new LinkedList<Long>();
 	    for (Lesson lesson : lessons) {
 		Set dbLessonUsers = lesson.getAllLearners();
@@ -883,16 +888,20 @@
 	    // Fetching the user data
 	    List<LearnerProgress> learnerProgresses;
 	    List<GradebookUserLesson> gradebookUserLessons;
-	    if (allLearners == null || allLearners.isEmpty()) {
+	    if (allLearners.isEmpty()) {
 		learnerProgresses = new LinkedList<LearnerProgress>();
 		gradebookUserLessons = new LinkedList<GradebookUserLesson>();
 		
 	    } else {
 		learnerProgresses = learnerProgressDAO.getLearnerProgressForLessons(lessonIds);
 		gradebookUserLessons = gradebookDAO.getGradebookUserLessons(lessonIds);
 	    }
+	    
+	    //sort users by last name
+	    TreeSet<User> sortedLearners = new TreeSet<User>(new UserComparator());
+	    sortedLearners.addAll(allLearners);
 
-	    for (User learner : allLearners) {
+	    for (User learner : sortedLearners) {
 		i = 0;
 		ExcelCell[] userDataRow = new ExcelCell[numberOfCellsInARow];
 		userDataRow[i++] = new ExcelCell(learner.getLastName(), false);
Index: lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/util/UserComparator.java
===================================================================
diff -u
--- lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/util/UserComparator.java	(revision 0)
+++ lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/util/UserComparator.java	(revision 7ad79c50d0bc5a1021cae22a121c1123f3943db3)
@@ -0,0 +1,16 @@
+package org.lamsfoundation.lams.gradebook.util;
+
+import java.util.Comparator;
+
+import org.apache.commons.lang.builder.CompareToBuilder;
+import org.lamsfoundation.lams.usermanagement.User;
+
+/**
+ * Sorts users by last names.
+ */
+public class UserComparator implements Comparator<User> {
+    public int compare(User o1, User o2) {
+	return new CompareToBuilder().append(o1.getLastName(), o2.getLastName())
+		.append(o1.getFirstName(), o2.getFirstName()).append(o1.getLogin(), o2.getLogin()).toComparison();
+    }
+}