diff --git a/.changeset/olive-fans-beg.md b/.changeset/olive-fans-beg.md
new file mode 100644
index 000000000000..915c5a375a38
--- /dev/null
+++ b/.changeset/olive-fans-beg.md
@@ -0,0 +1,5 @@
+---
+"astro": patch
+---
+
+Updates `astro add` to handle installing peer dependencies with optional npm specifiers
diff --git a/packages/astro/src/cli/add/index.ts b/packages/astro/src/cli/add/index.ts
index e452f08d688d..7f0263bcb2e9 100644
--- a/packages/astro/src/cli/add/index.ts
+++ b/packages/astro/src/cli/add/index.ts
@@ -693,7 +693,16 @@ async function resolveRangeToInstallSpecifier(name: string, range: string): Prom
 	if (versions instanceof Error) return name;
 	// Filter out any prerelease versions
 	const stableVersions = versions.filter((v) => !v.includes('-'));
+	// Peer dependencies may sometimes use the `npm:` specifier, but `semver` package panics with it.
+	// Filter it out if so.
+	if (range.includes('npm:')) {
+		range = range
+			.split('||')
+			.filter((r) => !r.includes('npm:'))
+			.join('||');
+	}
 	const maxStable = maxSatisfying(stableVersions, range);
+	if (maxStable === null) return name;
 	return `${name}@^${maxStable}`;
 }