diff --git a/test/functional/p2p_compactblocks.py b/test/functional/p2p_compactblocks.py
--- a/test/functional/p2p_compactblocks.py
+++ b/test/functional/p2p_compactblocks.py
@@ -744,20 +744,20 @@
 
         block, _ = self.build_block_with_transactions(node, utxo, 10)
 
-        [l.clear_block_announcement() for l in listeners]
+        [listener.clear_block_announcement() for listener in listeners]
 
         node.submitblock(ToHex(block))
 
-        for l in listeners:
-            wait_until(lambda: l.received_block_announcement(),
+        for listener in listeners:
+            wait_until(lambda: listener.received_block_announcement(),
                        timeout=30, lock=mininode_lock)
         with mininode_lock:
-            for l in listeners:
-                assert "cmpctblock" in l.last_message
-                l.last_message["cmpctblock"].header_and_shortids.header.calc_sha256(
+            for listener in listeners:
+                assert "cmpctblock" in listener.last_message
+                listener.last_message["cmpctblock"].header_and_shortids.header.calc_sha256(
                 )
                 assert_equal(
-                    l.last_message["cmpctblock"].header_and_shortids.header.sha256, block.sha256)
+                    listener.last_message["cmpctblock"].header_and_shortids.header.sha256, block.sha256)
 
     # Test that we don't get disconnected if we relay a compact block with valid header,
     # but invalid transactions.
diff --git a/test/functional/test_framework/messages.py b/test/functional/test_framework/messages.py
--- a/test/functional/test_framework/messages.py
+++ b/test/functional/test_framework/messages.py
@@ -74,16 +74,16 @@
     return sha256(sha256(s))
 
 
-def ser_compact_size(l):
+def ser_compact_size(size):
     r = b""
-    if l < 253:
-        r = struct.pack("B", l)
-    elif l < 0x10000:
-        r = struct.pack("<BH", 253, l)
-    elif l < 0x100000000:
-        r = struct.pack("<BI", 254, l)
+    if size < 253:
+        r = struct.pack("B", size)
+    elif size < 0x10000:
+        r = struct.pack("<BH", 253, size)
+    elif size < 0x100000000:
+        r = struct.pack("<BI", 254, size)
     else:
-        r = struct.pack("<BQ", 255, l)
+        r = struct.pack("<BQ", 255, size)
     return r
 
 
@@ -149,9 +149,9 @@
 
 # ser_function_name: Allow for an alternate serialization function on the
 # entries in the vector.
-def ser_vector(l, ser_function_name=None):
-    r = ser_compact_size(len(l))
-    for i in l:
+def ser_vector(v, ser_function_name=None):
+    r = ser_compact_size(len(v))
+    for i in v:
         if ser_function_name:
             r += getattr(i, ser_function_name)()
         else:
@@ -168,9 +168,9 @@
     return r
 
 
-def ser_uint256_vector(l):
-    r = ser_compact_size(len(l))
-    for i in l:
+def ser_uint256_vector(v):
+    r = ser_compact_size(len(v))
+    for i in v:
         r += ser_uint256(i)
     return r
 
@@ -184,9 +184,9 @@
     return r
 
 
-def ser_string_vector(l):
-    r = ser_compact_size(len(l))
-    for sv in l:
+def ser_string_vector(v):
+    r = ser_compact_size(len(v))
+    for sv in v:
         r += ser_string(sv)
     return r
 
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -142,8 +142,8 @@
 
         process.wait()
         log_stdout.seek(0), log_stderr.seek(0)
-        [stdout, stderr] = [l.read().decode('utf-8')
-                            for l in (log_stdout, log_stderr)]
+        [stdout, stderr] = [log.read().decode('utf-8')
+                            for log in (log_stdout, log_stderr)]
         log_stdout.close(), log_stderr.close()
         if process.returncode == TEST_EXIT_PASSED and stderr == "":
             status = "Passed"
diff --git a/test/fuzz/test_runner.py b/test/fuzz/test_runner.py
--- a/test/fuzz/test_runner.py
+++ b/test/fuzz/test_runner.py
@@ -122,10 +122,10 @@
         logging.debug('Output: {}'.format(output))
         if not export_coverage:
             continue
-        for l in output.splitlines():
-            if 'INITED' in l:
+        for line in output.splitlines():
+            if 'INITED' in line:
                 with open(os.path.join(corpus, t + '_coverage'), 'w', encoding='utf-8') as cov_file:
-                    cov_file.write(l)
+                    cov_file.write(line)
                     break
 
 
diff --git a/test/lint/lint-python-format.py b/test/lint/lint-python-format.py
--- a/test/lint/lint-python-format.py
+++ b/test/lint/lint-python-format.py
@@ -194,7 +194,7 @@
     pattern = re.compile(r"(?:\"|')\s*\\?\s+%\s+(?:\\\s+)?.+$", re.MULTILINE)
     snippets = find_snippets(file)
     return dict(
-        [(l, s) for l, s in snippets.items() if pattern.search(s) is not None])
+        [(line, snippet) for line, snippet in snippets.items() if pattern.search(snippet) is not None])
 
 
 def main(file):