diff --git a/ocaml/tests/test_pub.py b/ocaml/tests/test_pub.py
index e4a883ee..be577685 100755
--- a/ocaml/tests/test_pub.py
+++ b/ocaml/tests/test_pub.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 
 import zmq
 import sys, os
diff --git a/ocaml/tests/test_task_server.py b/ocaml/tests/test_task_server.py
index dac14083..ebbb07ae 100755
--- a/ocaml/tests/test_task_server.py
+++ b/ocaml/tests/test_task_server.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 
 import zmq
 import sys, os
diff --git a/scripts/Hn.py b/scripts/Hn.py
index 0f938510..55a958f7 100644
--- a/scripts/Hn.py
+++ b/scripts/Hn.py
@@ -1,4 +1,5 @@
-#!/usr/bin/env python                                                                                                     
+#!/usr/bin/env python3
+
 import sys
 from math import *
 arg = sys.argv
diff --git a/scripts/qp_exc_energy.py b/scripts/qp_exc_energy.py
index 7e7f1d67..44136311 100755
--- a/scripts/qp_exc_energy.py
+++ b/scripts/qp_exc_energy.py
@@ -1,4 +1,5 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
+
 # Computes the error on the excitation energy of a CIPSI run.
 
 def student(p,df):
diff --git a/scripts/utility/qp_json.py b/scripts/utility/qp_json.py
index 09ffe1be..5cba9ff2 100644
--- a/scripts/utility/qp_json.py
+++ b/scripts/utility/qp_json.py
@@ -1,4 +1,5 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
+
 import os
 import json
 
diff --git a/src/nuclei/write_pt_charges.py b/src/nuclei/write_pt_charges.py
index f5007090..03ac859b 100644
--- a/src/nuclei/write_pt_charges.py
+++ b/src/nuclei/write_pt_charges.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python  
+#!/usr/bin/env python3
 import os
 import sys