diff --git a/REQUIREMENTS b/REQUIREMENTS
index 4a22e45..d0294e9 100644
--- a/REQUIREMENTS
+++ b/REQUIREMENTS
@@ -42,6 +42,7 @@ decorator==5.1.1; python_version >= '3.5'
 deprecated==1.2.13; python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'
 dnsdb2==1.1.4
 dnspython==2.2.0
+dnspython3
 domaintools-api==0.6.1
 easygui==0.98.2
 ebcdic==1.1.1