diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 207457b36f..93b736afd0 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -28,8 +28,9 @@ jobs:
           token: ${{ secrets.github_token }}
           prefix: ${{ github.ref }}
 
-      - run: ./gradlew build javadocJar publish --stacktrace
+      - run: ./gradlew build javadocJar checkVersion publish --stacktrace
         env:
           MAVEN_URL: ${{ secrets.MAVEN_URL }}
           MAVEN_USERNAME: ${{ secrets.MAVEN_USERNAME }}
           MAVEN_PASSWORD: ${{ secrets.MAVEN_PASSWORD }}
+          VALIDATE_BRANCH: true
diff --git a/build.gradle b/build.gradle
index e68a33c897..c2b305d8f3 100644
--- a/build.gradle
+++ b/build.gradle
@@ -24,6 +24,7 @@ plugins {
 	id 'java' // for jd gen
 	id 'org.cadixdev.licenser' version '0.5.1'
 	id 'net.fabricmc.filament' version '0.2.0'
+	id "org.ajoberstar.grgit" version "4.1.0"
 }
 
 def minecraft_version = "21w17a"
@@ -35,6 +36,13 @@ def build_number = ENV.BUILD_NUMBER ?: "local"
 def yarnVersion = "${minecraft_version}+build.$build_number"
 version = yarnVersion
 
+if (ENV.VALIDATE_BRANCH) {
+	def branch = grgit.branch.current().name
+	if (minecraft_version != branch) {
+		throw new IllegalStateException("Branch name (${branch}) does not match the mc version (${minecraft_version})")
+	}
+}
+
 repositories {
 	mavenCentral()
 	maven {
@@ -1037,6 +1045,20 @@ publishing {
 	}
 }
 
+// A task to ensure that the version being released has not already been released.
+task checkVersion {
+	doFirst {
+		def xml = new URL("https://maven.fabricmc.net/net/fabricmc/yarn/maven-metadata.xml").text
+		def metadata = new XmlSlurper().parseText(xml)
+		def versions = metadata.versioning.versions.version*.text();
+		if (versions.contains(version)) {
+			throw new RuntimeException("${version} has already been released!")
+		}
+	}
+}
+
+publish.mustRunAfter checkVersion
+
 void mapJar(File output, File input, File mappings, File libraries, String from, String to,
 		Action<TinyRemapper.Builder> action = { }) {
 	if (output.exists()) {