diff --git a/.github/workflows/slack-notifications.yml b/.github/workflows/slack-notifications.yml
index ce8696608f..aa94445085 100644
--- a/.github/workflows/slack-notifications.yml
+++ b/.github/workflows/slack-notifications.yml
@@ -6,6 +6,22 @@
 name: Slack Notifications
 
 on:
+  workflow_run:
+    workflows:
+      - Code Coverage Report
+      - Coding Standards
+      - End-to-end Tests
+      - JavaScript Tests
+      - PHP Compatibility
+      - PHPUnit Tests
+      - Test NPM
+      - Test old branches
+    types:
+      - completed
+    branches:
+      - '[3-4].[0-9]'
+      - '5.[0-8]'
+
   workflow_call:
     secrets:
       SLACK_GHA_SUCCESS_WEBHOOK:
@@ -21,6 +37,9 @@ on:
         description: 'The Slack webhook URL for a failed build.'
         required: true
 
+env:
+  CURRENT_BRANCH: ${{ github.event_name == 'workflow_run' && github.event.workflow_run.head_branch || github.ref_name }}
+
 jobs:
   # Gathers the details needed for Slack notifications.
   #
@@ -28,8 +47,11 @@ jobs:
   # submit data to Slack webhook URLs configured to post messages.
   #
   # Performs the following steps:
+  # - Retrieves the workflow ID (if necessary).
+  # - Retrieves the workflow URL (if necessary).
   # - Retrieves the previous workflow run and stores its conclusion.
   # - Sets the previous conclusion as an output.
+  # - Prepares the commit message.
   # - Constructs and stores a message payload as an output.
   prepare:
     name: Prepare notifications
@@ -42,6 +64,7 @@ jobs:
     steps:
       - name: Get the workflow ID
         id: current-workflow-id
+        if: ${{ github.event_name == 'push' }}
         uses: actions/github-script@441359b1a30438de65712c2fbca0abe4816fa667 # v5.0.0
         with:
           script: |
@@ -55,6 +78,7 @@ jobs:
       - name: Get the workflow URL
         id: current-workflow-url
         uses: actions/github-script@441359b1a30438de65712c2fbca0abe4816fa667 # v5.0.0
+        if: ${{ github.event_name == 'push' }}
         with:
           script: |
             const workflow_run = await github.rest.actions.getWorkflowRun({
@@ -72,8 +96,8 @@ jobs:
             const previous_runs = await github.rest.actions.listWorkflowRuns({
               owner: '${{ github.repository_owner }}',
               repo: 'wordpress-develop',
-              workflow_id: ${{ steps.current-workflow-id.outputs.result }},
-              branch: '${{ github.ref_name }}',
+              workflow_id: ${{ github.event_name == 'workflow_run' && github.event.workflow_run.workflow_id || steps.current-workflow-id.outputs.result }},
+              branch: '${{ env.CURRENT_BRANCH }}',
               per_page: 1,
               page: 2,
             });
@@ -87,21 +111,21 @@ jobs:
         id: commit-message
         run: |
           COMMIT_MESSAGE=$(cat <<'EOF' | awk 'NR==1' | sed 's/`/\\`/g' | sed 's/\"/\\\\"/g'
-          ${{ github.event.head_commit.message }}
+          ${{ github.event_name == 'workflow_run' && github.event.workflow_run.head_commit.message || github.event.head_commit.message }}
           EOF
           )
           echo "::set-output name=commit_message_escaped::${COMMIT_MESSAGE}"
 
       - name: Construct payload and store as an output
         id: create-payload
-        run: echo "::set-output name=payload::{\"workflow_name\":\"${{ github.workflow }}\",\"ref_name\":\"${{ github.ref_name }}\",\"run_url\":\"${{ steps.current-workflow-url.outputs.result }}\",\"commit_message\":\"${{ steps.commit-message.outputs.commit_message_escaped }}\"}"
+        run: echo "::set-output name=payload::{\"workflow_name\":\"${{ github.workflow }}\",\"ref_name\":\"${{ env.CURRENT_BRANCH }}\",\"run_url\":\"${{ github.event_name == 'workflow_run' && github.event.workflow_run.html_url || steps.current-workflow-url.outputs.result }}\",\"commit_message\":\"${{ steps.commit-message.outputs.commit_message_escaped }}\"}"
 
   # Posts notifications when a workflow fails.
   failure:
     name: Failure notifications
     runs-on: ubuntu-latest
     needs: [ prepare ]
-    if: ${{ failure() }}
+    if: ${{ github.event_name == 'push' && failure() || github.event_name == 'workflow_run' && github.event.workflow_run.conclusion == 'failure' }}
 
     steps:
       - name: Post failure notifications to Slack
@@ -116,7 +140,7 @@ jobs:
     name: Fixed notifications
     runs-on: ubuntu-latest
     needs: [ prepare ]
-    if: ${{ needs.prepare.outputs.previous_conclusion == 'failure' && success() }}
+    if: ${{ needs.prepare.outputs.previous_conclusion == 'failure' && ( github.event_name == 'push' && success() || github.event_name == 'workflow_run' && github.event.workflow_run.conclusion == 'success' ) }}
 
     steps:
       - name: Post failure notifications to Slack
@@ -131,7 +155,7 @@ jobs:
     name: Success notifications
     runs-on: ubuntu-latest
     needs: [ prepare ]
-    if: ${{ success() }}
+    if: ${{ github.event_name == 'push' && success() || github.event_name == 'workflow_run' && github.event.workflow_run.conclusion == 'success' }}
 
     steps:
       - name: Post success notifications to Slack
@@ -146,7 +170,7 @@ jobs:
     name: Cancelled notifications
     runs-on: ubuntu-latest
     needs: [ prepare ]
-    if: ${{ cancelled() }}
+    if: ${{ github.event_name == 'push' && cancelled() || github.event_name == 'workflow_run' && github.event.workflow_run.conclusion == 'cancelled' }}
 
     steps:
       - name: Post cancelled notifications to Slack