diff --git a/examples/model_selection_ex.cpp b/examples/model_selection_ex.cpp
index 1994a914a..92208abae 100644
--- a/examples/model_selection_ex.cpp
+++ b/examples/model_selection_ex.cpp
@@ -25,7 +25,7 @@
 using namespace std;
 using namespace dlib;
 
-// The svm functions use column vectors to contain a lot of the data on which they they 
+// The svm functions use column vectors to contain a lot of the data on which they 
 // operate. So the first thing we do here is declare a convenient typedef.  
 
 // This typedef declares a matrix with 2 rows and 1 column.  It will be the
diff --git a/examples/rvm_ex.cpp b/examples/rvm_ex.cpp
index dfc8434d2..de2202984 100644
--- a/examples/rvm_ex.cpp
+++ b/examples/rvm_ex.cpp
@@ -27,7 +27,7 @@ using namespace dlib;
 
 int main()
 {
-    // The rvm functions use column vectors to contain a lot of the data on which they they 
+    // The rvm functions use column vectors to contain a lot of the data on which they 
     // operate. So the first thing we do here is declare a convenient typedef.  
 
     // This typedef declares a matrix with 2 rows and 1 column.  It will be the
diff --git a/examples/svm_ex.cpp b/examples/svm_ex.cpp
index 69c4933f3..868a8e031 100644
--- a/examples/svm_ex.cpp
+++ b/examples/svm_ex.cpp
@@ -27,7 +27,7 @@ using namespace dlib;
 
 int main()
 {
-    // The svm functions use column vectors to contain a lot of the data on which they they 
+    // The svm functions use column vectors to contain a lot of the data on which they 
     // operate. So the first thing we do here is declare a convenient typedef.  
 
     // This typedef declares a matrix with 2 rows and 1 column.  It will be the
diff --git a/examples/svm_pegasos_ex.cpp b/examples/svm_pegasos_ex.cpp
index 62cade4b1..8f8668faa 100644
--- a/examples/svm_pegasos_ex.cpp
+++ b/examples/svm_pegasos_ex.cpp
@@ -27,7 +27,7 @@ using namespace dlib;
 
 int main()
 {
-    // The svm functions use column vectors to contain a lot of the data on which they they 
+    // The svm functions use column vectors to contain a lot of the data on which they 
     // operate. So the first thing we do here is declare a convenient typedef.  
 
     // This typedef declares a matrix with 2 rows and 1 column.  It will be the