diff --git a/nullaway/src/main/java/com/uber/nullaway/handlers/LibraryModelsHandler.java b/nullaway/src/main/java/com/uber/nullaway/handlers/LibraryModelsHandler.java
index 799ef241ed..1ed32ebac6 100644
--- a/nullaway/src/main/java/com/uber/nullaway/handlers/LibraryModelsHandler.java
+++ b/nullaway/src/main/java/com/uber/nullaway/handlers/LibraryModelsHandler.java
@@ -452,6 +452,54 @@ private static class DefaultLibraryModels implements LibraryModels {
                     "org.junit.jupiter.api.Assertions",
                     "assertNotNull(java.lang.Object,java.util.function.Supplier<java.lang.String>)"),
                 0)
+            .put(methodRef("org.apache.commons.lang3.Validate", "<T>notNull(T)"), 0)
+            .put(
+                methodRef(
+                    "org.apache.commons.lang3.Validate",
+                    "<T>notNull(T,java.lang.String,java.lang.Object...)"),
+                0)
+            .put(
+                methodRef(
+                    "org.apache.commons.lang3.Validate",
+                    "<T>notEmpty(T[],java.lang.String,java.lang.Object...)"),
+                0)
+            .put(methodRef("org.apache.commons.lang3.Validate", "<T>notEmpty(T[])"), 0)
+            .put(
+                methodRef(
+                    "org.apache.commons.lang3.Validate",
+                    "<T>notEmpty(T,java.lang.String,java.lang.Object...)"),
+                0)
+            .put(methodRef("org.apache.commons.lang3.Validate", "<T>notEmpty(T)"), 0)
+            .put(
+                methodRef(
+                    "org.apache.commons.lang3.Validate",
+                    "<T>notBlank(T,java.lang.String,java.lang.Object...)"),
+                0)
+            .put(methodRef("org.apache.commons.lang3.Validate", "<T>notBlank(T)"), 0)
+            .put(
+                methodRef(
+                    "org.apache.commons.lang3.Validate",
+                    "<T>noNullElements(T[],java.lang.String,java.lang.Object...)"),
+                0)
+            .put(methodRef("org.apache.commons.lang3.Validate", "<T>noNullElements(T[])"), 0)
+            .put(
+                methodRef(
+                    "org.apache.commons.lang3.Validate",
+                    "<T>noNullElements(T,java.lang.String,java.lang.Object...)"),
+                0)
+            .put(methodRef("org.apache.commons.lang3.Validate", "<T>noNullElements(T)"), 0)
+            .put(
+                methodRef(
+                    "org.apache.commons.lang3.Validate",
+                    "<T>validIndex(T[],int,java.lang.String,java.lang.Object...)"),
+                0)
+            .put(methodRef("org.apache.commons.lang3.Validate", "<T>validIndex(T[],int)"), 0)
+            .put(
+                methodRef(
+                    "org.apache.commons.lang3.Validate",
+                    "<T>validIndex(T,int,java.lang.String,java.lang.Object...)"),
+                0)
+            .put(methodRef("org.apache.commons.lang3.Validate", "<T>validIndex(T,int)"), 0)
             .build();
 
     private static final ImmutableSetMultimap<MethodRef, Integer> EXPLICITLY_NULLABLE_PARAMETERS =
diff --git a/nullaway/src/test/java/com/uber/nullaway/NullAwayFrameworkTests.java b/nullaway/src/test/java/com/uber/nullaway/NullAwayFrameworkTests.java
index d3678632e8..8a41d2fd18 100644
--- a/nullaway/src/test/java/com/uber/nullaway/NullAwayFrameworkTests.java
+++ b/nullaway/src/test/java/com/uber/nullaway/NullAwayFrameworkTests.java
@@ -454,4 +454,386 @@ public void defaultLibraryModelsClassCast() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void apacheValidateNotNull() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String s) {",
+            "    Validate.notNull(s);",
+            "    int l = s.length();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateNotNullWithMessage() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String s) {",
+            "    Validate.notNull(s, \"Message\");",
+            "    int l = s.length();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateArrayNotEmptyWithMessage() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String[] s) {",
+            "    Validate.notEmpty(s, \"Message\");",
+            "    int l = s.length;",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateArrayNotEmpty() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String[] s) {",
+            "    Validate.notEmpty(s);",
+            "    int l = s.length;",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateListNotEmptyWithMessage() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "import java.util.List;",
+            "public class Foo {",
+            "  public void bar(@Nullable List<String> s) {",
+            "    Validate.notEmpty(s, \"Message\");",
+            "    int l = s.size();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateListNotEmpty() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "import java.util.List;",
+            "public class Foo {",
+            "  public void bar(@Nullable List<String> s) {",
+            "    Validate.notEmpty(s);",
+            "    int l = s.size();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateMapNotEmptyWithMessage() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "import java.util.Map;",
+            "public class Foo {",
+            "  public void bar(@Nullable Map<String, String> s) {",
+            "    Validate.notEmpty(s, \"Message\");",
+            "    int l = s.size();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateMapNotEmpty() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "import java.util.Map;",
+            "public class Foo {",
+            "  public void bar(@Nullable Map<String, String> s) {",
+            "    Validate.notEmpty(s);",
+            "    int l = s.size();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateStringNotEmptyWithMessage() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String s) {",
+            "    Validate.notEmpty(s, \"Message\");",
+            "    int l = s.length();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateStringNotEmpty() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String s) {",
+            "    Validate.notEmpty(s);",
+            "    int l = s.length();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateStringNotBlankWithMessage() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String s) {",
+            "    Validate.notBlank(s, \"Message\");",
+            "    int l = s.length();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateStringNotBlank() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String s) {",
+            "    Validate.notBlank(s);",
+            "    int l = s.length();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateArrayNoNullElementsWithMessage() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String[] s) {",
+            "    Validate.noNullElements(s, \"Message\");",
+            "    int l = s.length;",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateArrayNoNullElements() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String[] s) {",
+            "    Validate.noNullElements(s);",
+            "    int l = s.length;",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateIterableNoNullElementsWithMessage() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "import java.util.Iterator;",
+            "public class Foo {",
+            "  public void bar(@Nullable Iterable<String> s) {",
+            "    Validate.noNullElements(s, \"Message\");",
+            "    Iterator<String> l = s.iterator();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateIterableNoNullElements() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "import java.util.Iterator;",
+            "public class Foo {",
+            "  public void bar(@Nullable Iterable<String> s) {",
+            "    Validate.noNullElements(s);",
+            "    Iterator<String> l = s.iterator();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateArrayValidIndexWithMessage() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String[] s) {",
+            "    Validate.validIndex(s, 0, \"Message\");",
+            "    int l = s.length;",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateArrayValidIndex() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String[] s) {",
+            "    Validate.validIndex(s, 0);",
+            "    int l = s.length;",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateCollectionValidIndexWithMessage() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "import java.util.List;",
+            "public class Foo {",
+            "  public void bar(@Nullable List<String> s) {",
+            "    Validate.validIndex(s, 0, \"Message\");",
+            "    int l = s.size();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateCollectionValidIndex() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "import java.util.List;",
+            "public class Foo {",
+            "  public void bar(@Nullable List<String> s) {",
+            "    Validate.validIndex(s, 0);",
+            "    int l = s.size();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateStringValidIndexWithMessage() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String s) {",
+            "    Validate.validIndex(s, 0, \"Message\");",
+            "    int l = s.length();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void apacheValidateStringValidIndex() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Foo.java",
+            "package com.uber;",
+            "import org.apache.commons.lang3.Validate;",
+            "import org.jetbrains.annotations.Nullable;",
+            "public class Foo {",
+            "  public void bar(@Nullable String s) {",
+            "    Validate.validIndex(s, 0);",
+            "    int l = s.length();",
+            "  }",
+            "}")
+        .doTest();
+  }
 }