diff --git a/.ci/complement_package.gotpl b/.ci/complement_package.gotpl
index e1625fd31fe44ad4ddf8c66044e2046ea4ae5d1f..2dd5e5e0e695a90b8f08ce066994e3723417eb8c 100644
--- a/.ci/complement_package.gotpl
+++ b/.ci/complement_package.gotpl
@@ -27,10 +27,10 @@ which is under the Unlicense licence.
         {{- . -}}{{- "\n" -}}
     {{- end -}}
     {{- with .TestCases -}}
-        {{- /* Failing tests are first */ -}}
+        {{- /* Passing tests are first */ -}}
         {{- range . -}}
-            {{- if and (ne .Result "PASS") (ne .Result "SKIP") -}}
-                ::group::{{ "\033" }}[0;31m❌{{ " " }}{{- .Name -}}
+            {{- if eq .Result "PASS" -}}
+                ::group::{{ "\033" }}[0;32m✅{{ " " }}{{- .Name -}}
                 {{- "\033" -}}[0;37m ({{if $settings.ShowTestStatus}}{{.Result}}; {{end}}{{ .Duration -}}
                 {{- with .Coverage -}}
                     , coverage: {{ . }}%
@@ -47,7 +47,6 @@ which is under the Unlicense licence.
             {{- end -}}
         {{- end -}}
 
-
         {{- /* Then skipped tests are second */ -}}
         {{- range . -}}
             {{- if eq .Result "SKIP" -}}
@@ -68,11 +67,10 @@ which is under the Unlicense licence.
             {{- end -}}
         {{- end -}}
 
-
-        {{- /* Then passing tests are last */ -}}
+        {{- /* and failing tests are last */ -}}
         {{- range . -}}
-            {{- if eq .Result "PASS" -}}
-                ::group::{{ "\033" }}[0;32m✅{{ " " }}{{- .Name -}}
+            {{- if and (ne .Result "PASS") (ne .Result "SKIP") -}}
+                ::group::{{ "\033" }}[0;31m❌{{ " " }}{{- .Name -}}
                 {{- "\033" -}}[0;37m ({{if $settings.ShowTestStatus}}{{.Result}}; {{end}}{{ .Duration -}}
                 {{- with .Coverage -}}
                     , coverage: {{ . }}%
diff --git a/.ci/scripts/gotestfmt b/.ci/scripts/gotestfmt
new file mode 100755
index 0000000000000000000000000000000000000000..83e0ec63613cb7a03b5556f9dcf7d91aefcdf44e
--- /dev/null
+++ b/.ci/scripts/gotestfmt
@@ -0,0 +1,21 @@
+#!/bin/bash
+#
+# wraps `gotestfmt`, hiding output from successful packages unless
+# all tests passed.
+
+set -o pipefail
+set -e
+
+# tee the test results to a log, whilst also piping them into gotestfmt,
+# telling it to hide successful results, so that we can clearly see
+# unsuccessful results.
+tee complement.log | gotestfmt -hide successful-packages
+
+# gotestfmt will exit non-zero if there were any failures, so if we got to this
+# point, we must have had a successful result.
+echo "All tests successful; showing all test results"
+
+# Pipe the test results back through gotestfmt, showing all results.
+# The log file consists of JSON lines giving the test results, interspersed
+# with regular stdout lines (including reports of downloaded packages).
+grep '^{"Time":' complement.log | gotestfmt
diff --git a/.github/workflows/latest_deps.yml b/.github/workflows/latest_deps.yml
index f263cf612dc54b1f33ee03aa959f013a2eac1230..7dac617c4bec9acdd811f76faa9ea17d0c87c110 100644
--- a/.github/workflows/latest_deps.yml
+++ b/.github/workflows/latest_deps.yml
@@ -163,7 +163,7 @@ jobs:
 
       - run: |
           set -o pipefail
-          TEST_ONLY_IGNORE_POETRY_LOCKFILE=1 POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
+          TEST_ONLY_IGNORE_POETRY_LOCKFILE=1 POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | synapse/.ci/scripts/gotestfmt
         shell: bash
         name: Run Complement Tests
 
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 144cb9ffaac222cf0cd5162eaf0045fa3862fa4a..3e6d718a7c4d5921262a04e60a4ec50d18216584 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -354,7 +354,7 @@ jobs:
 
       - run: |
           set -o pipefail
-          POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
+          POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | synapse/.ci/scripts/gotestfmt
         shell: bash
         name: Run Complement Tests
 
diff --git a/.github/workflows/twisted_trunk.yml b/.github/workflows/twisted_trunk.yml
index dd8e6fbb1cc90c6616b134996b33b5f071ac5b9f..0906101cc1c19b1e6130a18f48c9edc55291a824 100644
--- a/.github/workflows/twisted_trunk.yml
+++ b/.github/workflows/twisted_trunk.yml
@@ -137,7 +137,7 @@ jobs:
 
       - run: |
           set -o pipefail
-          TEST_ONLY_SKIP_DEP_HASH_VERIFICATION=1 POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
+          TEST_ONLY_SKIP_DEP_HASH_VERIFICATION=1 POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | synapse/.ci/scripts/gotestfmt
         shell: bash
         name: Run Complement Tests
 
diff --git a/changelog.d/13639.misc b/changelog.d/13639.misc
new file mode 100644
index 0000000000000000000000000000000000000000..de4e4d12063255c7de0469e91dac4c6694e6d7d8
--- /dev/null
+++ b/changelog.d/13639.misc
@@ -0,0 +1 @@
+Improve readability of Complement CI logs by printing failure results last.