diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 54527eb..07b222e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -28,7 +28,7 @@ jobs:
       - run:
           # for git tests
           git config --global user.email "scalafmt@scalameta.org" && git config --global user.name "scalafmt"
-      - run: sbt plugin/scripted
+      - run: sbt plugin/scripted "++ 3.x" compile
 
   formatting:
     runs-on: ubuntu-latest
diff --git a/build.sbt b/build.sbt
index f42c202..4e89452 100644
--- a/build.sbt
+++ b/build.sbt
@@ -34,6 +34,7 @@ inThisBuild(List(
   ),
   resolvers ++= Resolver.sonatypeOssRepos("public"),
   scalaVersion := "2.12.20",
+  crossScalaVersions += "3.3.4",
   packageDoc / publishArtifact := insideCI.value,
   packageSrc / publishArtifact := insideCI.value,
 ))
@@ -47,14 +48,27 @@ lazy val plugin = project.enablePlugins(SbtPlugin).settings(
   moduleName := "sbt-scalafmt",
   libraryDependencies ++= List(
     "com.googlecode.java-diff-utils" % "diffutils" % "1.3.0",
-    "org.scalameta" %% "scalafmt-sysops" % scalafmtVersion,
-    "org.scalameta" %% "scalafmt-dynamic" % scalafmtVersion,
+    "org.scalameta" %% "scalafmt-sysops" % scalafmtVersion cross
+      CrossVersion.for3Use2_13,
+    "org.scalameta" %% "scalafmt-dynamic" % scalafmtVersion cross
+      CrossVersion.for3Use2_13,
   ),
   scriptedBufferLog := false,
   scriptedLaunchOpts += s"-Dplugin.version=${version.value}",
   // For compat reasons we have this in here to ensure we are testing against 1.2.8
   // We honestly probably don't need to, so if this ever causes issues, rip it out.
-  pluginCrossBuild / sbtVersion := "1.2.8",
+  pluginCrossBuild / sbtVersion := {
+    scalaBinaryVersion.value match {
+      case "2.12" => "1.2.8"
+      case _ => "2.0.0-M2"
+    }
+  },
+  conflictWarning := {
+    scalaBinaryVersion.value match {
+      case "3" => ConflictWarning("warn", Level.Warn, false)
+      case _ => conflictWarning.value
+    }
+  },
 )
 
 // For some reason, it doesn't work if this is defined in globalSettings in PublishPlugin.
diff --git a/plugin/src/main/scala/org/scalafmt/sbt/ScalafmtPlugin.scala b/plugin/src/main/scala/org/scalafmt/sbt/ScalafmtPlugin.scala
index 5160f6b..fe6b313 100644
--- a/plugin/src/main/scala/org/scalafmt/sbt/ScalafmtPlugin.scala
+++ b/plugin/src/main/scala/org/scalafmt/sbt/ScalafmtPlugin.scala
@@ -4,7 +4,9 @@ import java.io.OutputStreamWriter
 import java.nio.file.Path
 
 import sbt.Keys._
-import sbt._
+// format: off
+import sbt.{given, _}
+// format: on
 import sbt.librarymanagement.MavenRepository
 import sbt.util.CacheImplicits._
 import sbt.util.CacheStoreFactory
@@ -396,8 +398,8 @@ object ScalafmtPlugin extends AutoPlugin {
   private def getScalafmtSourcesTask(
       f: (Seq[File], Seq[File], FormatSession) => InitTask,
   ) = Def.taskDyn[Unit] {
-    val sources = unmanagedSources.in(scalafmt).?.value.getOrElse(Seq.empty)
-    val dirs = unmanagedSourceDirectories.in(scalafmt).?.value.getOrElse(Nil)
+    val sources = (scalafmt / unmanagedSources).?.value.getOrElse(Seq.empty)
+    val dirs = (scalafmt / unmanagedSourceDirectories).?.value.getOrElse(Nil)
     getScalafmtTask(f)(sources, dirs, scalaConfig.value)
   }
 
@@ -462,10 +464,10 @@ object ScalafmtPlugin extends AutoPlugin {
     scalafmtCheck := getScalafmtSourcesTask(scalafmtCheckTask).value,
     scalafmtSbtCheck := getScalafmtSbtTasks(scalafmtSbtCheckTask).value,
     scalafmtDoFormatOnCompile := Def.settingDyn {
-      if (scalafmtOnCompile.value) scalafmt.in(resolvedScoped.value.scope)
+      if (scalafmtOnCompile.value) resolvedScoped.value.scope / scalafmt
       else Def.task(())
     }.value,
-    sources.in(Compile) := sources.in(Compile)
+    Compile / sources := (Compile / sources)
       .dependsOn(scalafmtDoFormatOnCompile).value,
     scalafmtOnly := {
       val files = spaceDelimited("<files>").parsed
@@ -509,7 +511,7 @@ object ScalafmtPlugin extends AutoPlugin {
     )
 
   override def buildSettings: Seq[Def.Setting[_]] =
-    Seq(scalafmtConfig := baseDirectory.in(ThisBuild).value / ".scalafmt.conf")
+    Seq(scalafmtConfig := (ThisBuild / baseDirectory).value / ".scalafmt.conf")
 
   override def globalSettings: Seq[Def.Setting[_]] = Seq(
     scalafmtFilter := "",