diff --git a/.github/workflows/test-coverage.yaml b/.github/workflows/test-coverage.yaml
new file mode 100644
index 0000000..60447cd
--- /dev/null
+++ b/.github/workflows/test-coverage.yaml
@@ -0,0 +1,71 @@
+# Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
+# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+
+name: test-coverage
+
+permissions:
+  contents: read
+  id-token: write
+
+jobs:
+  test-coverage:
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: r-lib/actions/setup-r@v2
+        with:
+          use-public-rspm: true
+
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: any::covr, any::xml2
+          needs: coverage
+
+      - name: Test coverage
+        run: |
+          cov <- covr::package_coverage(
+            quiet = FALSE,
+            clean = FALSE,
+            install_path = file.path(normalizePath(Sys.getenv("RUNNER_TEMP"), winslash = "/"), "package")
+          )
+          print(cov)
+          pct <- round(covr::percent_coverage(cov), 2)
+          cat(sprintf("Overall coverage: %s%%\n", pct))
+          writeLines(as.character(pct), "coverage-percent.txt")
+          covr::to_cobertura(cov)
+        shell: Rscript {0}
+
+      - name: Report coverage percent
+        run: |
+          echo "Overall package coverage: $(cat coverage-percent.txt)%"
+
+      - uses: codecov/codecov-action@fb8b3582c8e4def4969c97caa2f19720cb33a72f # v7
+        with:
+          fail_ci_if_error: true
+          files: ./cobertura.xml
+          plugins: noop
+          disable_search: true
+          use_oidc: true
+
+      - name: Show testthat output
+        if: always()
+        run: |
+          ## --------------------------------------------------------------------
+          find '${{ runner.temp }}/package' -name 'testthat.Rout*' -exec cat '{}' \; || true
+        shell: bash
+
+      - name: Upload test results
+        if: failure()
+        uses: actions/upload-artifact@v7
+        with:
+          name: coverage-test-failures
+          path: ${{ runner.temp }}/package
diff --git a/README.md b/README.md
index a508338..ed9a355 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,10 @@
 # referent
 
+<!-- badges: start -->
+[![test-coverage](https://github.com/bbuchsbaum/referent/actions/workflows/test-coverage.yaml/badge.svg)](https://github.com/bbuchsbaum/referent/actions/workflows/test-coverage.yaml)
+[![Codecov test coverage](https://codecov.io/gh/bbuchsbaum/referent/branch/main/graph/badge.svg)](https://app.codecov.io/gh/bbuchsbaum/referent?branch=main)
+<!-- badges: end -->
+
 Distributional reference models and individual deviation scores.
 
 `referent` estimates the conditional predictive distribution of one or more