diff --git a/jc/utils.py b/jc/utils.py
index 3fc8df6f..0d679ded 100644
--- a/jc/utils.py
+++ b/jc/utils.py
@@ -603,6 +603,7 @@ class timestamp:
             {'id': 1800, 'format': '%d/%b/%Y:%H:%M:%S %z', 'locale': None},  # Common Log Format: 10/Oct/2000:13:55:36 -0700
             {'id': 2000, 'format': '%a %d %b %Y %I:%M:%S %p %Z', 'locale': None},  # en_US.UTF-8 local format (found in upower cli output): Tue 23 Mar 2021 04:12:11 PM UTC
             {'id': 3000, 'format': '%a %d %b %Y %I:%M:%S %p', 'locale': None},  # en_US.UTF-8 local format with non-UTC tz (found in upower cli output): Tue 23 Mar 2021 04:12:11 PM IST
+            {'id': 3500, 'format': '%a, %d %b %Y %H:%M:%S %Z', 'locale': None},  # HTTP header time format (always GMT so assume UTC): Wed, 31 Jan 2024 00:39:28 GMT
             {'id': 4000, 'format': '%A %d %B %Y %I:%M:%S %p %Z', 'locale': None},  # European-style local format (found in upower cli output): Tuesday 01 October 2019 12:50:41 PM UTC
             {'id': 5000, 'format': '%A %d %B %Y %I:%M:%S %p', 'locale': None},  # European-style local format with non-UTC tz (found in upower cli output): Tuesday 01 October 2019 12:50:41 PM IST
             {'id': 6000, 'format': '%a %b %d %I:%M:%S %p %Z %Y', 'locale': None},  # en_US.UTF-8 format (found in date cli): Wed Mar 24 06:16:19 PM UTC 2021
@@ -621,7 +622,7 @@ class timestamp:
         )
 
         # from https://www.timeanddate.com/time/zones/
-        # only removed UTC timezone and added known non-UTC offsets
+        # only removed UTC & GMT timezones and added known non-UTC offsets
         tz_abbr: set[str] = {
             'A', 'ACDT', 'ACST', 'ACT', 'ACWST', 'ADT', 'AEDT', 'AEST', 'AET', 'AFT', 'AKDT',
             'AKST', 'ALMT', 'AMST', 'AMT', 'ANAST', 'ANAT', 'AQTT', 'ART', 'AST', 'AT', 'AWDT',
@@ -630,7 +631,7 @@ class timestamp:
             'CHOT', 'CHUT', 'CIDST', 'CIST', 'CKT', 'CLST', 'CLT', 'COT', 'CST', 'CT', 'CVT', 'CXT',
             'ChST', 'D', 'DAVT', 'DDUT', 'E', 'EASST', 'EAST', 'EAT', 'ECT', 'EDT', 'EEST', 'EET',
             'EGST', 'EGT', 'EST', 'ET', 'F', 'FET', 'FJST', 'FJT', 'FKST', 'FKT', 'FNT', 'G',
-            'GALT', 'GAMT', 'GET', 'GFT', 'GILT', 'GMT', 'GST', 'GYT', 'H', 'HDT', 'HKT', 'HOVST',
+            'GALT', 'GAMT', 'GET', 'GFT', 'GILT', 'GST', 'GYT', 'H', 'HDT', 'HKT', 'HOVST',
             'HOVT', 'HST', 'I', 'ICT', 'IDT', 'IOT', 'IRDT', 'IRKST', 'IRKT', 'IRST', 'IST', 'JST',
             'K', 'KGT', 'KOST', 'KRAST', 'KRAT', 'KST', 'KUYT', 'L', 'LHDT', 'LHST', 'LINT', 'M',
             'MAGST', 'MAGT', 'MART', 'MAWT', 'MDT', 'MHT', 'MMT', 'MSD', 'MSK', 'MST', 'MT', 'MUT',
@@ -686,6 +687,9 @@ class timestamp:
         # UTC can also be indicated with 'Z' for Zulu time (ISO-8601). Convert to 'UTC'
         data = data.replace('Z', 'UTC')
 
+        # GMT and UTC are practically equivalent. Convert to 'UTC'
+        data = data.replace('GMT', 'UTC')
+
         if 'UTC' in data:
             utc_tz = True
             if 'UTC+' in data or 'UTC-' in data:
diff --git a/tests/test_jc_utils.py b/tests/test_jc_utils.py
index f5aea7a9..0ed5dad1 100644
--- a/tests/test_jc_utils.py
+++ b/tests/test_jc_utils.py
@@ -57,6 +57,8 @@ class MyTests(unittest.TestCase):
             'Tue 23 Mar 2021 04:12:11 PM UTC': {'string': 'Tue 23 Mar 2021 04:12:11 PM UTC', 'format': 2000, 'naive': 1616541131, 'utc': 1616515931},
             # en_US.UTF-8 local format with non-UTC tz (found in upower cli output)
             'Tue 23 Mar 2021 04:12:11 PM IST': {'string': 'Tue 23 Mar 2021 04:12:11 PM IST', 'format': 3000, 'naive': 1616541131, 'utc': None},
+            # HTTP header time format (always GMT so assume UTC)
+            'Wed, 31 Jan 2024 00:39:28 GMT': {'string': 'Wed, 31 Jan 2024 00:39:28 GMT', 'format': 3500, 'naive': 1706690368, 'utc': 1706661568},
             # European local format (found in upower cli output)
             'Tuesday 01 October 2019 12:50:41 PM UTC': {'string': 'Tuesday 01 October 2019 12:50:41 PM UTC', 'format': 4000, 'naive': 1569959441, 'utc': 1569934241},
             # European local format with non-UTC tz (found in upower cli output)