diff --git a/src/main/java/com/icoderman/woocommerce/oauth/OAuthSignature.java b/src/main/java/com/icoderman/woocommerce/oauth/OAuthSignature.java
index 1cb5997..989a426 100644
--- a/src/main/java/com/icoderman/woocommerce/oauth/OAuthSignature.java
+++ b/src/main/java/com/icoderman/woocommerce/oauth/OAuthSignature.java
@@ -130,6 +130,7 @@ private static String percentEncode(String s) {
                     // OAuth encodes some characters differently:
                     .replace(SpecialSymbol.PLUS.getPlain(), SpecialSymbol.PLUS.getEncoded())
                     .replace(SpecialSymbol.STAR.getPlain(), SpecialSymbol.STAR.getEncoded())
+                    .replace(SpecialSymbol.PERCENT.getPlain(), SpecialSymbol.PERCENT.getEncoded())
                     .replace(SpecialSymbol.TILDE.getEncoded(), SpecialSymbol.TILDE.getPlain());
         } catch (UnsupportedEncodingException e) {
             throw new RuntimeException(e.getMessage(), e);
diff --git a/src/main/java/com/icoderman/woocommerce/oauth/SpecialSymbol.java b/src/main/java/com/icoderman/woocommerce/oauth/SpecialSymbol.java
index c677460..36eed22 100644
--- a/src/main/java/com/icoderman/woocommerce/oauth/SpecialSymbol.java
+++ b/src/main/java/com/icoderman/woocommerce/oauth/SpecialSymbol.java
@@ -9,6 +9,7 @@ public enum SpecialSymbol {
     EQUAL("=", "%3D"),
     PLUS("+", "%2B"),
     STAR("*", "%2A"),
+    PERCENT("%", "%25"),
     TILDE("~", "%7E");
 
     private String plain;