diff --git a/src/enc/config.c b/src/enc/config.c
index 467013d8..0908498b 100644
--- a/src/enc/config.c
+++ b/src/enc/config.c
@@ -9,7 +9,6 @@
 //
 // Author: Skal (pascal.massimino@gmail.com)
 
-#include <assert.h>
 #include "../webp/encode.h"
 
 #if defined(__cplusplus) || defined(c_plusplus)
diff --git a/src/enc/cost.c b/src/enc/cost.c
index c28adc64..fed34376 100644
--- a/src/enc/cost.c
+++ b/src/enc/cost.c
@@ -9,8 +9,6 @@
 //
 // Author: Skal (pascal.massimino@gmail.com)
 
-#include <assert.h>
-
 #include "./cost.h"
 
 #if defined(__cplusplus) || defined(c_plusplus)
diff --git a/src/enc/filter.c b/src/enc/filter.c
index 68e8b28e..22903372 100644
--- a/src/enc/filter.c
+++ b/src/enc/filter.c
@@ -9,8 +9,6 @@
 //
 // Author: somnath@google.com (Somnath Banerjee)
 
-#include <math.h>
-
 #include "./vp8enci.h"
 
 #if defined(__cplusplus) || defined(c_plusplus)
diff --git a/src/enc/frame.c b/src/enc/frame.c
index cc7e50b5..d23d23ed 100644
--- a/src/enc/frame.c
+++ b/src/enc/frame.c
@@ -11,7 +11,6 @@
 
 #include <stdlib.h>
 #include <string.h>
-#include <assert.h>
 #include <math.h>
 
 #include "./vp8enci.h"
diff --git a/src/enc/iterator.c b/src/enc/iterator.c
index 20df95d6..2ea85823 100644
--- a/src/enc/iterator.c
+++ b/src/enc/iterator.c
@@ -9,7 +9,6 @@
 //
 // Author: Skal (pascal.massimino@gmail.com)
 
-#include <stdlib.h>
 #include <string.h>
 
 #include "./vp8enci.h"
diff --git a/src/enc/layer.c b/src/enc/layer.c
index 22f25798..ce39ca84 100644
--- a/src/enc/layer.c
+++ b/src/enc/layer.c
@@ -9,7 +9,6 @@
 //
 // Author: Skal (pascal.massimino@gmail.com)
 
-#include <assert.h>
 #include <stdlib.h>
 
 #include "./vp8enci.h"
diff --git a/src/enc/syntax.c b/src/enc/syntax.c
index 3678cc88..cc577678 100644
--- a/src/enc/syntax.c
+++ b/src/enc/syntax.c
@@ -10,7 +10,6 @@
 // Author: Skal (pascal.massimino@gmail.com)
 
 #include <assert.h>
-#include <math.h>
 
 #include "./vp8enci.h"
 #include "../dec/webpi.h"  // For chunk-size constants.
diff --git a/src/enc/vp8enci.h b/src/enc/vp8enci.h
index 46094a27..7bbd0068 100644
--- a/src/enc/vp8enci.h
+++ b/src/enc/vp8enci.h
@@ -12,7 +12,7 @@
 #ifndef WEBP_ENC_VP8ENCI_H_
 #define WEBP_ENC_VP8ENCI_H_
 
-#include "string.h"     // for memcpy()
+#include <string.h>     // for memcpy()
 #include "../webp/encode.h"
 #include "../dsp/dsp.h"
 #include "../utils/bit_writer.h"