diff --git a/src/release-specification.test.ts b/src/release-specification.test.ts
index 7e8c107..3dfe295 100644
--- a/src/release-specification.test.ts
+++ b/src/release-specification.test.ts
@@ -242,7 +242,13 @@ packages:
       await withSandbox(async (sandbox) => {
         const project = buildMockProject({
           workspacePackages: {
-            a: buildMockPackage('a'),
+            a: buildMockPackage('a', {
+              unvalidatedManifest: {
+                dependencies: {
+                  b: '1.0.0',
+                },
+              },
+            }),
             b: buildMockPackage('b'),
             c: buildMockPackage('c'),
             d: buildMockPackage('d'),
@@ -678,6 +684,116 @@ Your release spec could not be processed due to the following issues:
 
 The release spec file has been retained for you to edit again and make the necessary fixes. Once you've done this, re-run this tool.
 
+${releaseSpecificationPath}
+`.trim(),
+        );
+      });
+    });
+
+    it('throws if there are any packages listed in the release but their dependent via "dependencies" is not listed', async () => {
+      await withSandbox(async (sandbox) => {
+        const project = buildMockProject({
+          workspacePackages: {
+            a: buildMockPackage('a', {
+              hasChangesSinceLatestRelease: true,
+            }),
+            b: buildMockPackage('b', {
+              hasChangesSinceLatestRelease: false,
+              unvalidatedManifest: {
+                dependencies: {
+                  a: '1.0.0',
+                },
+              },
+            }),
+          },
+        });
+        const releaseSpecificationPath = path.join(
+          sandbox.directoryPath,
+          'release-spec',
+        );
+        await fs.promises.writeFile(
+          releaseSpecificationPath,
+          YAML.stringify({
+            packages: {
+              a: 'major',
+            },
+          }),
+        );
+
+        await expect(
+          validateReleaseSpecification(project, releaseSpecificationPath),
+        ).rejects.toThrow(
+          `
+Your release spec could not be processed due to the following issues:
+
+* The following packages, which depends on released package a, are missing.
+
+  - b
+
+ Consider including them in the release spec so that they won't break in production.
+
+  If you are ABSOLUTELY SURE that this won't occur, however, and want to postpone the release of a package, then list it with a directive of "intentionally-skip". For example:
+
+    packages:
+      b: intentionally-skip
+
+The release spec file has been retained for you to edit again and make the necessary fixes. Once you've done this, re-run this tool.
+
+${releaseSpecificationPath}
+`.trim(),
+        );
+      });
+    });
+
+    it('throws if there are any packages listed in the release but their dependent via "peerDependencies" is not listed', async () => {
+      await withSandbox(async (sandbox) => {
+        const project = buildMockProject({
+          workspacePackages: {
+            a: buildMockPackage('a', {
+              hasChangesSinceLatestRelease: true,
+            }),
+            b: buildMockPackage('b', {
+              hasChangesSinceLatestRelease: false,
+              unvalidatedManifest: {
+                peerDependencies: {
+                  a: '1.0.0',
+                },
+              },
+            }),
+          },
+        });
+        const releaseSpecificationPath = path.join(
+          sandbox.directoryPath,
+          'release-spec',
+        );
+        await fs.promises.writeFile(
+          releaseSpecificationPath,
+          YAML.stringify({
+            packages: {
+              a: 'major',
+            },
+          }),
+        );
+
+        await expect(
+          validateReleaseSpecification(project, releaseSpecificationPath),
+        ).rejects.toThrow(
+          `
+Your release spec could not be processed due to the following issues:
+
+* The following packages, which depends on released package a, are missing.
+
+  - b
+
+ Consider including them in the release spec so that they won't break in production.
+
+  If you are ABSOLUTELY SURE that this won't occur, however, and want to postpone the release of a package, then list it with a directive of "intentionally-skip". For example:
+
+    packages:
+      b: intentionally-skip
+
+The release spec file has been retained for you to edit again and make the necessary fixes. Once you've done this, re-run this tool.
+
 ${releaseSpecificationPath}
 `.trim(),
         );
diff --git a/src/release-specification.ts b/src/release-specification.ts
index 3dc89fb..42adcca 100644
--- a/src/release-specification.ts
+++ b/src/release-specification.ts
@@ -1,5 +1,6 @@
 import fs, { WriteStream } from 'fs';
 import YAML from 'yaml';
+import { diff } from 'semver';
 import { Editor } from './editor';
 import { readFile } from './fs';
 import {
@@ -304,6 +305,79 @@ export async function validateReleaseSpecification(
     },
   );
 
+  Object.keys(unvalidatedReleaseSpecification.packages).forEach(
+    (packageName) => {
+      const versionSpecifierOrDirective =
+        unvalidatedReleaseSpecification.packages[packageName];
+      const pkg = project.workspacePackages[packageName];
+
+      if (
+        versionSpecifierOrDirective === 'major' ||
+        (isValidSemver(versionSpecifierOrDirective) &&
+          diff(
+            pkg.validatedManifest.version,
+            versionSpecifierOrDirective as string,
+          ) === 'major')
+      ) {
+        const missingDependents = Object.values(
+          project.workspacePackages,
+        ).filter((dependent) => {
+          const { dependencies, peerDependencies } =
+            dependent.unvalidatedManifest;
+          const isDependent =
+            (dependencies && hasProperty(dependencies, packageName)) ||
+            (peerDependencies && hasProperty(peerDependencies, packageName));
+
+          if (!isDependent) {
+            return false;
+          }
+
+          const dependentVersionSpecifierOrDirective =
+            unvalidatedReleaseSpecification.packages[
+              dependent.validatedManifest.name
+            ];
+
+          return (
+            dependentVersionSpecifierOrDirective !== SKIP_PACKAGE_DIRECTIVE &&
+            dependentVersionSpecifierOrDirective !==
+              INTENTIONALLY_SKIP_PACKAGE_DIRECTIVE &&
+            !hasProperty(
+              IncrementableVersionParts,
+              dependentVersionSpecifierOrDirective,
+            ) &&
+            !isValidSemver(dependentVersionSpecifierOrDirective)
+          );
+        });
+
+        if (missingDependents.length > 0) {
+          errors.push({
+            message: [
+              `The following packages, which depends on released package ${packageName}, are missing.`,
+              missingDependents
+                .map((dependent) => `  - ${dependent.validatedManifest.name}`)
+                .join('\n'),
+              " Consider including them in the release spec so that they won't break in production.",
+              `  If you are ABSOLUTELY SURE that this won't occur, however, and want to postpone the release of a package, then list it with a directive of "intentionally-skip". For example:`,
+              YAML.stringify({
+                packages: missingDependents.reduce((object, dependent) => {
+                  return {
+                    ...object,
+                    [dependent.validatedManifest.name]:
+                      INTENTIONALLY_SKIP_PACKAGE_DIRECTIVE,
+                  };
+                }, {}),
+              })
+                .trim()
+                .split('\n')
+                .map((line) => `    ${line}`)
+                .join('\n'),
+            ].join('\n\n'),
+          });
+        }
+      }
+    },
+  );
+
   if (errors.length > 0) {
     const message = [
       'Your release spec could not be processed due to the following issues:',
diff --git a/tests/unit/helpers.ts b/tests/unit/helpers.ts
index ac2e0fc..79eb31f 100644
--- a/tests/unit/helpers.ts
+++ b/tests/unit/helpers.ts
@@ -4,7 +4,10 @@ import { SemVer } from 'semver';
 import { isPlainObject } from '@metamask/utils';
 import type { Package } from '../../src/package';
 import { PackageManifestFieldNames } from '../../src/package-manifest';
-import type { ValidatedPackageManifest } from '../../src/package-manifest';
+import type {
+  UnvalidatedPackageManifest,
+  ValidatedPackageManifest,
+} from '../../src/package-manifest';
 import type { Project } from '../../src/project';
 
 /**
@@ -35,6 +38,7 @@ type MockPackageOverrides = Omit<
     Partial<ValidatedPackageManifest>,
     PackageManifestFieldNames.Name | PackageManifestFieldNames.Version
   >;
+  unvalidatedManifest?: UnvalidatedPackageManifest;
 };
 
 /**
@@ -102,6 +106,7 @@ export function buildMockPackage(
 
   const {
     validatedManifest = {},
+    unvalidatedManifest = {},
     directoryPath = `/path/to/packages/${name}`,
     manifestPath = path.join(directoryPath, 'package.json'),
     changelogPath = path.join(directoryPath, 'CHANGELOG.md'),
@@ -110,7 +115,7 @@ export function buildMockPackage(
 
   return {
     directoryPath,
-    unvalidatedManifest: {},
+    unvalidatedManifest,
     validatedManifest: buildMockManifest({
       ...validatedManifest,
       [PackageManifestFieldNames.Name]: name,