diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index fc33672..c6b2adc 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -1,18 +1,59 @@
 name: 'Test setup-gazebo'
 on:
-  workflow_dispatch:
+  pull_request:
+  push:
+    branches:
+      - main
+      - "releases/*"
+  schedule:
+    # Run the CI automatically twice per day to look for flakyness.
+    - cron: "0 */12 * * *"
 jobs:
-  test_linux:
+  test_gazebo_install_ubuntu:
+    name: 'Check installation of Gazebo on Ubuntu'
     runs-on: ubuntu-latest
     container:
       image: ${{ matrix.docker_image }}
     strategy:
       fail-fast: false
       matrix:
-        docker_image:
-          - ubuntu:20.04
-          - ubuntu:22.04
+        gazebo_distribution:
+          - citadel
+          - fortress
+          - garden
+          - harmonic
+        include:
+          # Gazebo Citadel (Dec 2019 - Dec 2024)
+          - docker_image: ubuntu:focal
+            gazebo_distribution: citadel
+
+          # Gazebo Fortress (Sep 2021 - Sep 2026)
+          - docker_image: ubuntu:focal
+            gazebo_distribution: fortress
+
+          # Gazebo Garden (Sep 2022 - Nov 2024)
+          - docker_image: ubuntu:focal
+            gazebo_distribution: garden
+
+          # Gazebo Harmonic (Sep 2023 - Sep 2028)
+          - docker_image: ubuntu:jammy
+            gazebo_distribution: harmonic
     steps:
-      - uses: actions/checkout@v2
-      - name: 'Linux setup'
-        uses: ./
\ No newline at end of file
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4.0.2
+        with:
+          node-version: "20.x"
+      - name: 'Check Gazebo installation on Ubuntu runner'
+        uses: ./
+        with:
+          required-gazebo-distributions: ${{ matrix.gazebo_distribution }}
+      - name: 'Test Gazebo installation'
+        run: |
+          if command -v ign > /dev/null; then
+            ign gazebo --versions
+          elif command -v gz > /dev/null; then
+            gz sim --versions
+          else
+            echo "Neither ign nor gz command found"
+            exit 1
+          fi
diff --git a/action.yml b/action.yml
index 99c9be3..877158f 100644
--- a/action.yml
+++ b/action.yml
@@ -1,6 +1,20 @@
 name: 'Setup Gazebo release'
 description: |
   Install a Gazebo release on a Linux system
+required-gazebo-distributions:
+    description: |
+      List of Gazebo distributions to be installed.
+
+      Allowed Gazebo distributions
+      - citadel
+      - fortress
+      - garden
+      - harmonic
+
+      Multiple values can be passed using a whitespace delimited list
+      "fortress garden".
+    required: false
+    default: ''
 runs:
   using: node20
   main: dist/index.js
diff --git a/dist/index.js b/dist/index.js
index 5aaaf6a..402546c 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -26189,7 +26189,6 @@ exports.runAptGetInstall = void 0;
 const utils = __importStar(__nccwpck_require__(1314));
 const aptCommandLine = [
     "DEBIAN_FRONTEND=noninteractive",
-    "RTI_NC_LICENSE_ACCEPTED=yes",
     "apt-get",
     "install",
     "--no-install-recommends",
@@ -26286,7 +26285,7 @@ function configOs() {
         yield utils.exec("sudo", ["bash", "-c", "echo 'Etc/UTC' > /etc/timezone"]);
         yield utils.exec("sudo", ["apt-get", "update"]);
         // Install tools required to configure the worker system.
-        yield apt.runAptGetInstall(["curl", "gnupg2", "locales", "lsb-release"]);
+        yield apt.runAptGetInstall(["wget", "curl", "gnupg2", "locales", "lsb-release", "ca-certificates"]);
         // Select a locale supporting Unicode.
         yield utils.exec("sudo", ["locale-gen", "en_US", "en_US.UTF-8"]);
         core.exportVariable("LANG", "en_US.UTF-8");
@@ -26301,12 +26300,51 @@ function configOs() {
         yield apt.runAptGetInstall(["tzdata"]);
     });
 }
+/**
+ * Add OSRF APT repository key.
+ *
+ * This is necessary even when building from source to install colcon, vcs, etc.
+ */
+function addAptRepoKey() {
+    return __awaiter(this, void 0, void 0, function* () {
+        yield utils.exec("sudo", [
+            "bash",
+            "-c",
+            `wget https://packages.osrfoundation.org/gazebo.gpg -O \
+    /usr/share/keyrings/pkgs-osrf-archive-keyring.gpg`,
+        ]);
+    });
+}
+/**
+ * Add OSRF APT repository.
+ *
+ * @param ubuntuCodename the Ubuntu version codename
+ */
+function addAptRepo(ubuntuCodename) {
+    return __awaiter(this, void 0, void 0, function* () {
+        yield utils.exec("sudo", [
+            "bash",
+            "-c",
+            `echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/pkgs-osrf-archive-keyring.gpg] \
+    http://packages.osrfoundation.org/gazebo/ubuntu-stable ${ubuntuCodename} main" | \
+    sudo tee /etc/apt/sources.list.d/gazebo-stable.list > /dev/null`,
+        ]);
+        yield utils.exec("sudo", ["apt-get", "update"]);
+    });
+}
 /**
  * Install Gazebo on a Linux worker.
  */
 function runLinux() {
     return __awaiter(this, void 0, void 0, function* () {
         yield configOs();
+        yield addAptRepoKey();
+        // Add repo according to Ubuntu version
+        const ubuntuCodename = yield utils.determineDistribCodename();
+        yield addAptRepo(ubuntuCodename);
+        for (const gazeboDistro of utils.getRequiredGazeboDistributions()) {
+            yield apt.runAptGetInstall([`gz-${gazeboDistro}`]);
+        }
     });
 }
 exports.runLinux = runLinux;
@@ -26411,7 +26449,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 Object.defineProperty(exports, "__esModule", ({ value: true }));
-exports.determineDistribCodename = exports.exec = void 0;
+exports.getRequiredGazeboDistributions = exports.validateDistro = exports.determineDistribCodename = exports.exec = void 0;
 const actions_exec = __importStar(__nccwpck_require__(1514));
 const core = __importStar(__nccwpck_require__(2186));
 /**
@@ -26455,6 +26493,44 @@ function determineDistribCodename() {
     });
 }
 exports.determineDistribCodename = determineDistribCodename;
+// List of valid Gazebo distributions
+const validDistro = ["citadel", "fortress", "garden", "harmonic"];
+/**
+ * Validate all Gazebo input distribution names
+ *
+ * @param requiredGazeboDistributionsList
+ * @returns boolean Validity of Gazebo distribution
+ */
+function validateDistro(requiredGazeboDistributionsList) {
+    for (const gazeboDistro of requiredGazeboDistributionsList) {
+        if (validDistro.indexOf(gazeboDistro) <= -1) {
+            return false;
+        }
+    }
+    return true;
+}
+exports.validateDistro = validateDistro;
+/**
+ * Gets the input of the Gazebo distributions to be installed and
+ * validates them
+ *
+ * @returns string[] List of validated Gazebo distributions
+ */
+function getRequiredGazeboDistributions() {
+    let requiredGazeboDistributionsList = [];
+    const requiredGazeboDistributions = core.getInput("required-gazebo-distributions");
+    if (requiredGazeboDistributions) {
+        requiredGazeboDistributionsList = requiredGazeboDistributions.split(RegExp("\\s"));
+    }
+    else {
+        throw new Error("Input cannot be empty.");
+    }
+    if (!validateDistro(requiredGazeboDistributionsList)) {
+        throw new Error("Input has invalid distribution names.");
+    }
+    return requiredGazeboDistributionsList;
+}
+exports.getRequiredGazeboDistributions = getRequiredGazeboDistributions;
 
 
 /***/ }),
diff --git a/src/package_manager/apt.ts b/src/package_manager/apt.ts
index ea96257..91a3ba1 100644
--- a/src/package_manager/apt.ts
+++ b/src/package_manager/apt.ts
@@ -1,13 +1,12 @@
 import * as utils from "../utils";
 
 const aptCommandLine: string[] = [
-	"DEBIAN_FRONTEND=noninteractive",
-	"RTI_NC_LICENSE_ACCEPTED=yes",
-	"apt-get",
-	"install",
-	"--no-install-recommends",
-	"--quiet",
-	"--yes",
+  "DEBIAN_FRONTEND=noninteractive",
+  "apt-get",
+  "install",
+  "--no-install-recommends",
+  "--quiet",
+  "--yes",
 ];
 
 /**
@@ -24,5 +23,5 @@ const aptCommandLine: string[] = [
  * @returns Promise<number> exit code
  */
 export async function runAptGetInstall(packages: string[]): Promise<number> {
-	return utils.exec("sudo", aptCommandLine.concat(packages));
+  return utils.exec("sudo", aptCommandLine.concat(packages));
 }
\ No newline at end of file
diff --git a/src/setup-gazebo-linux.ts b/src/setup-gazebo-linux.ts
index 6392def..05acb33 100644
--- a/src/setup-gazebo-linux.ts
+++ b/src/setup-gazebo-linux.ts
@@ -4,55 +4,89 @@ import * as io from "@actions/io";
 import * as apt from "./package_manager/apt";
 import * as utils from "./utils";
 
-import * as path from "path";
-import fs from "fs";
-
 /**
  * Configure basic OS stuff.
  */
 async function configOs(): Promise<void> {
-	// When this action runs in a Docker image, sudo may be missing.
-	// This installs sudo to avoid having to handle both cases (action runs as
-	// root, action does not run as root) everywhere in the action.
-	try {
-		await io.which("sudo", true);
-	} catch (err) {
-		await utils.exec("apt-get", ["update"]);
-		await utils.exec("apt-get", [
-			"install",
-			"--no-install-recommends",
-			"--quiet",
-			"--yes",
-			"sudo",
-		]);
-	}
-
-	await utils.exec("sudo", ["bash", "-c", "echo 'Etc/UTC' > /etc/timezone"]);
-	await utils.exec("sudo", ["apt-get", "update"]);
-
-	// Install tools required to configure the worker system.
-	await apt.runAptGetInstall(["curl", "gnupg2", "locales", "lsb-release"]);
-
-	// Select a locale supporting Unicode.
-	await utils.exec("sudo", ["locale-gen", "en_US", "en_US.UTF-8"]);
-	core.exportVariable("LANG", "en_US.UTF-8");
-
-	// Enforce UTC time for consistency.
-	await utils.exec("sudo", ["bash", "-c", "echo 'Etc/UTC' > /etc/timezone"]);
-	await utils.exec("sudo", [
-		"ln",
-		"-sf",
-		"/usr/share/zoneinfo/Etc/UTC",
-		"/etc/localtime",
-	]);
-	await apt.runAptGetInstall(["tzdata"]);
+  // When this action runs in a Docker image, sudo may be missing.
+  // This installs sudo to avoid having to handle both cases (action runs as
+  // root, action does not run as root) everywhere in the action.
+  try {
+    await io.which("sudo", true);
+  } catch (err) {
+    await utils.exec("apt-get", ["update"]);
+    await utils.exec("apt-get", [
+      "install",
+      "--no-install-recommends",
+      "--quiet",
+      "--yes",
+      "sudo",
+    ]);
+  }
+
+  await utils.exec("sudo", ["bash", "-c", "echo 'Etc/UTC' > /etc/timezone"]);
+  await utils.exec("sudo", ["apt-get", "update"]);
+
+  // Install tools required to configure the worker system.
+  await apt.runAptGetInstall(["wget", "curl", "gnupg2", "locales", "lsb-release", "ca-certificates"]);
+
+  // Select a locale supporting Unicode.
+  await utils.exec("sudo", ["locale-gen", "en_US", "en_US.UTF-8"]);
+  core.exportVariable("LANG", "en_US.UTF-8");
+
+  // Enforce UTC time for consistency.
+  await utils.exec("sudo", ["bash", "-c", "echo 'Etc/UTC' > /etc/timezone"]);
+  await utils.exec("sudo", [
+    "ln",
+    "-sf",
+    "/usr/share/zoneinfo/Etc/UTC",
+    "/etc/localtime",
+  ]);
+  await apt.runAptGetInstall(["tzdata"]);
+}
+
+/**
+ * Add OSRF APT repository key.
+ *
+ * This is necessary even when building from source to install colcon, vcs, etc.
+ */
+async function addAptRepoKey(): Promise<void> {
+  await utils.exec("sudo", [
+    "bash",
+    "-c",
+    `wget https://packages.osrfoundation.org/gazebo.gpg -O \
+    /usr/share/keyrings/pkgs-osrf-archive-keyring.gpg`,
+  ]);
+}
+
+/**
+ * Add OSRF APT repository.
+ *
+ * @param ubuntuCodename the Ubuntu version codename
+ */
+async function addAptRepo(ubuntuCodename: string): Promise<void> {
+  await utils.exec("sudo", [
+    "bash",
+    "-c",
+    `echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/pkgs-osrf-archive-keyring.gpg] \
+    http://packages.osrfoundation.org/gazebo/ubuntu-stable ${ubuntuCodename} main" | \
+    sudo tee /etc/apt/sources.list.d/gazebo-stable.list > /dev/null`,
+  ]);
+  await utils.exec("sudo", ["apt-get", "update"]);
 }
 
 /**
  * Install Gazebo on a Linux worker.
  */
 export async function runLinux(): Promise<void> {
+  await configOs();
+  await addAptRepoKey();
 
-	await configOs();
+  // Add repo according to Ubuntu version
+  const ubuntuCodename = await utils.determineDistribCodename();
+  await addAptRepo(ubuntuCodename);
 
+  for (const gazeboDistro of utils.getRequiredGazeboDistributions()) {
+    await apt.runAptGetInstall([`gz-${gazeboDistro}`]);
+  }
 }
diff --git a/src/setup-gazebo.ts b/src/setup-gazebo.ts
index 361d43f..d4d00a7 100644
--- a/src/setup-gazebo.ts
+++ b/src/setup-gazebo.ts
@@ -7,10 +7,10 @@ async function run() {
   }
   catch (error) {
     let errorMessage = "Unknown error";
-		if (error instanceof Error) {
-			errorMessage = error.message;
-		}
-		core.setFailed(errorMessage);
+    if (error instanceof Error) {
+      errorMessage = error.message;
+    }
+    core.setFailed(errorMessage);
   }
 }
 
diff --git a/src/utils.ts b/src/utils.ts
index e99a37d..234449a 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -12,16 +12,16 @@ import * as im from "@actions/exec/lib/interfaces";
  * @returns Promise<number> exit code
  */
 export async function exec(
-	commandLine: string,
-	args?: string[],
-	options?: im.ExecOptions,
-	log_message?: string,
+  commandLine: string,
+  args?: string[],
+  options?: im.ExecOptions,
+  log_message?: string,
 ): Promise<number> {
-	const argsAsString = (args || []).join(" ");
-	const message = log_message || `Invoking "${commandLine} ${argsAsString}"`;
-	return core.group(message, () => {
-		return actions_exec.exec(commandLine, args, options);
-	});
+  const argsAsString = (args || []).join(" ");
+  const message = log_message || `Invoking "${commandLine} ${argsAsString}"`;
+  return core.group(message, () => {
+    return actions_exec.exec(commandLine, args, options);
+  });
 }
 
 /**
@@ -33,17 +33,59 @@ export async function exec(
  * @returns Promise<string> Ubuntu distribution codename (e.g. "focal")
  */
 export async function determineDistribCodename(): Promise<string> {
-	let distribCodename = "";
-	const options: im.ExecOptions = {};
-	options.listeners = {
-		stdout: (data: Buffer) => {
-			distribCodename += data.toString();
-		},
-	};
-	await exec(
-		"bash",
-		["-c", 'source /etc/lsb-release ; echo -n "$DISTRIB_CODENAME"'],
-		options,
-	);
-	return distribCodename;
+  let distribCodename = "";
+  const options: im.ExecOptions = {};
+  options.listeners = {
+    stdout: (data: Buffer) => {
+      distribCodename += data.toString();
+    },
+  };
+  await exec(
+    "bash",
+    ["-c", 'source /etc/lsb-release ; echo -n "$DISTRIB_CODENAME"'],
+    options,
+  );
+  return distribCodename;
+}
+
+// List of valid Gazebo distributions
+const validDistro: string[] = ["citadel", "fortress", "garden", "harmonic"];
+
+/**
+ * Validate all Gazebo input distribution names
+ *
+ * @param requiredGazeboDistributionsList
+ * @returns boolean Validity of Gazebo distribution
+ */
+export function validateDistro(
+  requiredGazeboDistributionsList: string[],
+): boolean {
+  for (const gazeboDistro of requiredGazeboDistributionsList) {
+    if (validDistro.indexOf(gazeboDistro) <= -1) {
+      return false;
+    }
+  }
+  return true;
+}
+
+/**
+ * Gets the input of the Gazebo distributions to be installed and
+ * validates them
+ *
+ * @returns string[] List of validated Gazebo distributions
+ */
+export function getRequiredGazeboDistributions(): string[] {
+  let requiredGazeboDistributionsList: string[] = [];
+  const requiredGazeboDistributions = core.getInput("required-gazebo-distributions");
+  if (requiredGazeboDistributions) {
+    requiredGazeboDistributionsList = requiredGazeboDistributions.split(
+      RegExp("\\s"),
+    );
+  } else {
+    throw new Error("Input cannot be empty.");
+  }
+  if (!validateDistro(requiredGazeboDistributionsList)) {
+    throw new Error("Input has invalid distribution names.");
+  }
+  return requiredGazeboDistributionsList;
 }
\ No newline at end of file