diff --git a/pom.xml b/pom.xml
index 34a9235b..87f36a19 100644
--- a/pom.xml
+++ b/pom.xml
@@ -85,9 +85,9 @@
       <version>1.2.2</version>
     </dependency>
     <dependency>
-      <groupId>org.checkerframework</groupId>
-      <artifactId>checker-qual</artifactId>
-      <version>3.48.2</version>
+      <groupId>org.jspecify</groupId>
+      <artifactId>jspecify</artifactId>
+      <version>1.0.0</version>
     </dependency>
   </dependencies>
 
diff --git a/src/main/java/com/google/testing/compile/CompilationSubject.java b/src/main/java/com/google/testing/compile/CompilationSubject.java
index 2fd3f393..22b093ba 100644
--- a/src/main/java/com/google/testing/compile/CompilationSubject.java
+++ b/src/main/java/com/google/testing/compile/CompilationSubject.java
@@ -57,7 +57,7 @@
 import javax.tools.JavaFileManager.Location;
 import javax.tools.JavaFileObject;
 import javax.tools.StandardLocation;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /** A {@link Truth} subject for a {@link Compilation}. */
 public final class CompilationSubject extends Subject {
diff --git a/src/main/java/com/google/testing/compile/CompilationSubjectFactory.java b/src/main/java/com/google/testing/compile/CompilationSubjectFactory.java
index 75eda87a..b2ff5ff4 100644
--- a/src/main/java/com/google/testing/compile/CompilationSubjectFactory.java
+++ b/src/main/java/com/google/testing/compile/CompilationSubjectFactory.java
@@ -18,7 +18,7 @@
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
 import com.google.common.truth.Truth;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /** A {@link Truth} subject factory for a {@link Compilation}. */
 final class CompilationSubjectFactory implements Subject.Factory<CompilationSubject, Compilation> {
diff --git a/src/main/java/com/google/testing/compile/Compiler.java b/src/main/java/com/google/testing/compile/Compiler.java
index f77d7e56..827f2912 100644
--- a/src/main/java/com/google/testing/compile/Compiler.java
+++ b/src/main/java/com/google/testing/compile/Compiler.java
@@ -45,7 +45,7 @@
 import javax.tools.JavaFileObject;
 import javax.tools.StandardJavaFileManager;
 import javax.tools.StandardLocation;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /** An object that can {@link #compile} Java source files. */
 @AutoValue
diff --git a/src/main/java/com/google/testing/compile/InMemoryJavaFileManager.java b/src/main/java/com/google/testing/compile/InMemoryJavaFileManager.java
index d7f540a2..b2641b3a 100644
--- a/src/main/java/com/google/testing/compile/InMemoryJavaFileManager.java
+++ b/src/main/java/com/google/testing/compile/InMemoryJavaFileManager.java
@@ -43,7 +43,7 @@
 import javax.tools.SimpleJavaFileObject;
 import javax.tools.StandardJavaFileManager;
 import javax.tools.StandardLocation;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * A file manager implementation that stores all output in memory.
diff --git a/src/main/java/com/google/testing/compile/JavaFileObjectSubject.java b/src/main/java/com/google/testing/compile/JavaFileObjectSubject.java
index 29211b6f..80df4894 100644
--- a/src/main/java/com/google/testing/compile/JavaFileObjectSubject.java
+++ b/src/main/java/com/google/testing/compile/JavaFileObjectSubject.java
@@ -36,7 +36,7 @@
 import java.nio.charset.Charset;
 import java.util.function.BiFunction;
 import javax.tools.JavaFileObject;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /** Assertions about {@link JavaFileObject}s. */
 public final class JavaFileObjectSubject extends Subject {
diff --git a/src/main/java/com/google/testing/compile/JavaFileObjectSubjectFactory.java b/src/main/java/com/google/testing/compile/JavaFileObjectSubjectFactory.java
index daf7fc47..174c29af 100644
--- a/src/main/java/com/google/testing/compile/JavaFileObjectSubjectFactory.java
+++ b/src/main/java/com/google/testing/compile/JavaFileObjectSubjectFactory.java
@@ -18,7 +18,7 @@
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
 import javax.tools.JavaFileObject;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /** A factory for {@link JavaFileObjectSubject}s. */
 final class JavaFileObjectSubjectFactory
diff --git a/src/main/java/com/google/testing/compile/JavaSourceSubjectFactory.java b/src/main/java/com/google/testing/compile/JavaSourceSubjectFactory.java
index 9e807ab5..ba477913 100644
--- a/src/main/java/com/google/testing/compile/JavaSourceSubjectFactory.java
+++ b/src/main/java/com/google/testing/compile/JavaSourceSubjectFactory.java
@@ -18,7 +18,7 @@
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
 import javax.tools.JavaFileObject;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * A <a href="https://github.com/truth0/truth">Truth</a> {@link Subject.Factory} similar to
diff --git a/src/main/java/com/google/testing/compile/JavaSourcesSubject.java b/src/main/java/com/google/testing/compile/JavaSourcesSubject.java
index a088c411..1687c2e8 100644
--- a/src/main/java/com/google/testing/compile/JavaSourcesSubject.java
+++ b/src/main/java/com/google/testing/compile/JavaSourcesSubject.java
@@ -55,7 +55,7 @@
 import javax.tools.Diagnostic.Kind;
 import javax.tools.JavaFileManager;
 import javax.tools.JavaFileObject;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * A <a href="https://github.com/truth0/truth">Truth</a> {@link Subject} that evaluates the result
diff --git a/src/main/java/com/google/testing/compile/JavaSourcesSubjectFactory.java b/src/main/java/com/google/testing/compile/JavaSourcesSubjectFactory.java
index 89cb800b..517e21e1 100644
--- a/src/main/java/com/google/testing/compile/JavaSourcesSubjectFactory.java
+++ b/src/main/java/com/google/testing/compile/JavaSourcesSubjectFactory.java
@@ -18,7 +18,7 @@
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
 import javax.tools.JavaFileObject;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * A <a href="https://github.com/truth0/truth">Truth</a> {@link Subject.Factory} for creating
diff --git a/src/main/java/com/google/testing/compile/MoreTrees.java b/src/main/java/com/google/testing/compile/MoreTrees.java
index 5a10e044..9c4fd1d6 100644
--- a/src/main/java/com/google/testing/compile/MoreTrees.java
+++ b/src/main/java/com/google/testing/compile/MoreTrees.java
@@ -35,7 +35,7 @@
 import com.sun.source.util.TreePathScanner;
 import java.util.Arrays;
 import java.util.Optional;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * A class containing methods which are useful for gaining access to {@code Tree} instances from
diff --git a/src/main/java/com/google/testing/compile/TreeDiffer.java b/src/main/java/com/google/testing/compile/TreeDiffer.java
index 87344c22..9df5585d 100644
--- a/src/main/java/com/google/testing/compile/TreeDiffer.java
+++ b/src/main/java/com/google/testing/compile/TreeDiffer.java
@@ -54,7 +54,7 @@
 import javax.lang.model.element.Name;
 import javax.lang.model.type.TypeMirror;
 import javax.tools.JavaFileObject;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * A class for determining how two compilation {@code Tree}s differ from each other.
diff --git a/src/main/java/com/google/testing/compile/TreeDifference.java b/src/main/java/com/google/testing/compile/TreeDifference.java
index 1170bbfd..f62481a1 100644
--- a/src/main/java/com/google/testing/compile/TreeDifference.java
+++ b/src/main/java/com/google/testing/compile/TreeDifference.java
@@ -22,7 +22,7 @@
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.sun.source.tree.Tree;
 import com.sun.source.util.TreePath;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * A data structure describing the set of syntactic differences between two {@link Tree}s.
diff --git a/src/main/java/com/google/testing/compile/TypeEnumerator.java b/src/main/java/com/google/testing/compile/TypeEnumerator.java
index a385ac75..ac65357d 100644
--- a/src/main/java/com/google/testing/compile/TypeEnumerator.java
+++ b/src/main/java/com/google/testing/compile/TypeEnumerator.java
@@ -29,7 +29,7 @@
 import com.sun.source.tree.Tree;
 import com.sun.source.util.TreeScanner;
 import java.util.Set;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * Provides information about the set of types that are declared by a {@code CompilationUnitTree}.
diff --git a/src/main/java/com/google/testing/compile/package-info.java b/src/main/java/com/google/testing/compile/package-info.java
index 789c8900..24015b5a 100644
--- a/src/main/java/com/google/testing/compile/package-info.java
+++ b/src/main/java/com/google/testing/compile/package-info.java
@@ -83,6 +83,8 @@
  * </pre>
  */
 @CheckReturnValue
+@NullMarked
 package com.google.testing.compile;
 
 import com.google.errorprone.annotations.CheckReturnValue;
+import org.jspecify.annotations.NullMarked;