diff --git a/.gitattributes b/.gitattributes
index b8beb0f1f..55f14568b 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -12,6 +12,7 @@
 /.github/workflows/codecov.yml linguist-generated
 /.github/workflows/integ.yml linguist-generated
 /.github/workflows/issue-label-assign.yml linguist-generated
+/.github/workflows/large-pr-checker.yml linguist-generated
 /.github/workflows/pr-labeler.yml linguist-generated
 /.github/workflows/pull-request-lint.yml linguist-generated
 /.github/workflows/release.yml linguist-generated
diff --git a/.github/workflows/large-pr-checker.yml b/.github/workflows/large-pr-checker.yml
new file mode 100644
index 000000000..fe3462172
--- /dev/null
+++ b/.github/workflows/large-pr-checker.yml
@@ -0,0 +1,44 @@
+# ~~ Generated by projen. To modify, edit .projenrc.ts and run "npx projen".
+
+name: large-pr-checker
+on:
+  pull_request:
+    branches:
+      - main
+    types:
+      - labeled
+      - edited
+      - opened
+      - reopened
+      - unlabeled
+jobs:
+  check:
+    name: Check PR size
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+    if: ${{ !contains(github.event.pull_request.labels.*.name, 'pr/exempt-size-check') }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - id: fetch_target_branch
+        run: git fetch origin main
+      - id: get_total_lines_changed
+        run: |-
+          size=$(git diff --shortstat origin/main ':(exclude)*.md' ':(exclude)*.test.ts' ':(exclude)*.yml' \
+                  | awk '{ print $4+$6 }' \
+                  | awk -F- '{print $NF}' \
+                  | bc)
+                  
+                  echo "Total lines changed: $size"
+                  echo "total_lines_changed=$size" >> $GITHUB_OUTPUT
+      - id: comment_pr
+        if: ${{ fromJSON(steps.get_total_lines_changed.outputs.total_lines_changed) > fromJSON(1000) }}
+        uses: thollander/actions-comment-pull-request@v2
+        with:
+          comment_tag: pr_size
+          mode: recreate
+          message: Total lines changed ${{ steps.get_total_lines_changed.outputs.total_lines_changed }} is greater than 1000. Please consider breaking this PR down.
+      - id: fail
+        if: ${{ fromJSON(steps.get_total_lines_changed.outputs.total_lines_changed) > fromJSON(1000) }}
+        run: exit 1
diff --git a/.gitignore b/.gitignore
index 9892d6ebb..9a5c7ad8a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -51,5 +51,6 @@ jspm_packages/
 !/.github/workflows/codecov.yml
 !/.github/workflows/issue-label-assign.yml
 !/.github/workflows/pr-labeler.yml
+!/.github/workflows/large-pr-checker.yml
 !/.projenrc.ts
 !/.github/workflows/release.yml
diff --git a/.projen/files.json b/.projen/files.json
index 12528934f..9b83c55db 100644
--- a/.projen/files.json
+++ b/.projen/files.json
@@ -10,6 +10,7 @@
     ".github/workflows/codecov.yml",
     ".github/workflows/integ.yml",
     ".github/workflows/issue-label-assign.yml",
+    ".github/workflows/large-pr-checker.yml",
     ".github/workflows/pr-labeler.yml",
     ".github/workflows/pull-request-lint.yml",
     ".github/workflows/release.yml",
diff --git a/.projenrc.ts b/.projenrc.ts
index 67aa2692f..42f5a2090 100644
--- a/.projenrc.ts
+++ b/.projenrc.ts
@@ -9,6 +9,7 @@ import { CodeCovWorkflow } from './projenrc/codecov';
 import { ESLINT_RULES } from './projenrc/eslint';
 import { IssueLabeler } from './projenrc/issue-labeler';
 import { JsiiBuild } from './projenrc/jsii';
+import { LargePrChecker } from './projenrc/large-pr-checker';
 import { PrLabeler } from './projenrc/pr-labeler';
 import { RecordPublishingTimestamp } from './projenrc/record-publishing-timestamp';
 import { S3DocsPublishing } from './projenrc/s3-docs-publishing';
@@ -1514,4 +1515,8 @@ new CodeCovWorkflow(repo, {
 new IssueLabeler(repo);
 new PrLabeler(repo);
 
+new LargePrChecker(repo, {
+  excludeFiles: ['*.md', '*.test.ts', '*.yml'],
+});
+
 repo.synth();
diff --git a/projenrc/large-pr-checker.ts b/projenrc/large-pr-checker.ts
new file mode 100644
index 000000000..af4fac4a6
--- /dev/null
+++ b/projenrc/large-pr-checker.ts
@@ -0,0 +1,85 @@
+import { github, Component } from 'projen';
+import { JobPermission } from 'projen/lib/github/workflows-model';
+import type { TypeScriptProject } from 'projen/lib/typescript';
+
+export interface LargePrCheckerProps {
+  /**
+   * The number of lines changed in the PR that will trigger a comment and a failure.
+   *
+   * @default 1000
+   */
+  readonly maxLinesChanged?: number;
+
+  /**
+   * A list of files to exclude from the line count.
+   *
+   * @default - none
+   */
+  readonly excludeFiles?: string[];
+}
+
+export class LargePrChecker extends Component {
+  private readonly workflow: github.GithubWorkflow;
+
+  constructor(repo: TypeScriptProject, props: LargePrCheckerProps = {}) {
+    super(repo);
+
+    if (!repo.github) {
+      throw new Error('Given repository does not have a GitHub component');
+    }
+
+    const maxLinesChanged = props.maxLinesChanged ?? 1000;
+    const excludeFiles = (props.excludeFiles ?? [])
+      .map((pattern) => `':(exclude)${pattern}'`)
+      .join(' ');
+
+    this.workflow = repo.github.addWorkflow('large-pr-checker');
+    this.workflow.on({
+      pullRequest: {
+        branches: ['main'],
+        types: ['labeled', 'edited', 'opened', 'reopened', 'unlabeled'],
+      },
+    });
+
+    this.workflow.addJob('check', {
+      name: 'Check PR size',
+      if: '${{ !contains(github.event.pull_request.labels.*.name, \'pr/exempt-size-check\') }}',
+      runsOn: ['ubuntu-latest'],
+      permissions: {
+        pullRequests: JobPermission.WRITE,
+      },
+      steps: [
+        github.WorkflowSteps.checkout(),
+        {
+          id: 'fetch_target_branch',
+          run: 'git fetch origin main',
+        },
+        {
+          id: 'get_total_lines_changed',
+          run: `size=$(git diff --shortstat origin/main ${excludeFiles} \\
+        | awk '{ print $4+$6 }' \\
+        | awk -F- '{print $NF}' \\
+        | bc)
+        
+        echo "Total lines changed: $size"
+        echo "total_lines_changed=$size" >> $GITHUB_OUTPUT`,
+        },
+        {
+          id: 'comment_pr',
+          if: `$\{{ fromJSON(steps.get_total_lines_changed.outputs.total_lines_changed) > fromJSON(${maxLinesChanged}) }}`,
+          uses: 'thollander/actions-comment-pull-request@v2',
+          with: {
+            comment_tag: 'pr_size',
+            mode: 'recreate',
+            message: `Total lines changed $\{{ steps.get_total_lines_changed.outputs.total_lines_changed }} is greater than ${maxLinesChanged}. Please consider breaking this PR down.`,
+          },
+        },
+        {
+          id: 'fail',
+          if: `$\{{ fromJSON(steps.get_total_lines_changed.outputs.total_lines_changed) > fromJSON(${maxLinesChanged}) }}`,
+          run: 'exit 1',
+        },
+      ],
+    });
+  }
+}