diff --git a/changelogs/server_server/newsfragments/1278.clarification b/changelogs/server_server/newsfragments/1278.clarification
new file mode 100644
index 00000000..41a6299a
--- /dev/null
+++ b/changelogs/server_server/newsfragments/1278.clarification
@@ -0,0 +1 @@
+Remove `origin` field from transactions which was redundant and not enforced to be present by Synapse.
diff --git a/data/api/server-server/definitions/single_pdu_transaction.yaml b/data/api/server-server/definitions/single_pdu_transaction.yaml
index 74b9744d..f9b8f1d6 100644
--- a/data/api/server-server/definitions/single_pdu_transaction.yaml
+++ b/data/api/server-server/definitions/single_pdu_transaction.yaml
@@ -29,4 +29,4 @@ properties:
       properties: {}
       example:
         $ref: "../examples/minimal_pdu.json"
-required: ['origin', 'origin_server_ts', 'pdus']
+required: ['origin_server_ts', 'pdus']
diff --git a/data/api/server-server/definitions/transaction.yaml b/data/api/server-server/definitions/transaction.yaml
index e20204e0..a4bcf762 100644
--- a/data/api/server-server/definitions/transaction.yaml
+++ b/data/api/server-server/definitions/transaction.yaml
@@ -17,11 +17,6 @@ description: Transaction
 example:
   $ref: "../examples/transaction.json"
 properties:
-  origin:
-    type: string
-    description: |-
-      The `server_name` of the homeserver sending this transaction.
-    example: "example.org"
   origin_server_ts:
     type: integer
     format: int64
@@ -44,4 +39,4 @@ properties:
       properties: {}
       example:
         $ref: "../examples/minimal_pdu.json"
-required: ['origin', 'origin_server_ts', 'pdus']
+required: ['origin_server_ts', 'pdus']
diff --git a/data/api/server-server/definitions/unlimited_pdu_transaction.yaml b/data/api/server-server/definitions/unlimited_pdu_transaction.yaml
index 003daee5..e7654614 100644
--- a/data/api/server-server/definitions/unlimited_pdu_transaction.yaml
+++ b/data/api/server-server/definitions/unlimited_pdu_transaction.yaml
@@ -30,4 +30,4 @@ properties:
       properties: {}
       example:
         $ref: "../examples/minimal_pdu.json"
-required: ['origin', 'origin_server_ts', 'pdus']
+required: ['origin_server_ts', 'pdus']
diff --git a/data/api/server-server/examples/transaction.json b/data/api/server-server/examples/transaction.json
index bbc661d9..c30d5929 100644
--- a/data/api/server-server/examples/transaction.json
+++ b/data/api/server-server/examples/transaction.json
@@ -1,5 +1,4 @@
 {
-    "origin": "matrix.org",
     "origin_server_ts": 1234567890,
     "pdus": [{
         "$ref": "minimal_pdu.json"