diff --git a/packages/sparql-qlever/src/importer.ts b/packages/sparql-qlever/src/importer.ts
index 6f6cf383..c6078f34 100644
--- a/packages/sparql-qlever/src/importer.ts
+++ b/packages/sparql-qlever/src/importer.ts
@@ -252,15 +252,30 @@ export class Importer implements ImporterInterface {
     const metadataFile = `${this.options.indexName}.meta-data.json`;
     const localName = basename(file);
     const decompressCommand = localName.toLowerCase().endsWith('.zip')
-      ? `unzip -p '${localName}'`
-      : `(gunzip -c '${localName}' 2>/dev/null || cat '${localName}')`;
+      ? `unzip -p ${shellQuote(localName)}`
+      : `(gunzip -c ${shellQuote(localName)} 2>/dev/null || cat ${shellQuote(localName)})`;
     const indexTask = await this.options.taskRunner.run(
-      `${decompressCommand} | qlever-index ${flags} && cat ${metadataFile}`,
+      `${decompressCommand} | qlever-index ${flags} && cat ${shellQuote(metadataFile)}`,
     );
     return await this.options.taskRunner.wait(indexTask);
   }
 }
 
+/**
+ * POSIX-quote a value for safe interpolation into a shell command: wrap it in
+ * single quotes and escape any embedded single quote as `'\''`.
+ *
+ * Without this, a data filename containing an apostrophe — e.g. a dataset
+ * titled `'s-Hertogenbosch`, whose distribution URL maps to a local file like
+ * `…Erfgoed+'s-Hertogenbosch.nt` — would terminate the surrounding quotes, so
+ * `cat`/`gunzip` would read a non-existent path and feed `qlever-index` empty
+ * input. The index then "succeeds" with 0 triples, the import is treated as
+ * failed, and every distribution (and the JSON-LD fallback) fails the same way.
+ */
+function shellQuote(value: string): string {
+  return `'${value.replace(/'/g, "'\\''")}'`;
+}
+
 type fileFormat = 'nt' | 'nq' | 'ttl';
 
 /**
diff --git a/packages/sparql-qlever/test/importer.test.ts b/packages/sparql-qlever/test/importer.test.ts
index 94d3ee89..847d6b3c 100644
--- a/packages/sparql-qlever/test/importer.test.ts
+++ b/packages/sparql-qlever/test/importer.test.ts
@@ -13,6 +13,7 @@ import {
   utimes,
 } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
+import { execFileSync } from 'node:child_process';
 import { TaskRunner } from '@lde/task-runner';
 
 function makeDistributions(): Distribution[] {
@@ -331,6 +332,48 @@ describe('Importer', () => {
       ]);
     });
 
+    it('shell-escapes data filenames containing single quotes', async () => {
+      // A dataset titled e.g. "'s-Hertogenbosch" maps to a local filename with
+      // an apostrophe. Naive single-quoting (`cat '<name>'`) lets the apostrophe
+      // terminate the quote, so cat/gunzip read a non-existent path and feed
+      // qlever-index empty input — silently indexing 0 triples.
+      const trickyFile = join(
+        tempDir,
+        "Dataset+Beeldbank+Erfgoed+'s-Hertogenbosch.ttl",
+      );
+      await copyFile(dataFile, trickyFile);
+
+      const runner = stubTaskRunner(42);
+      const importer = new Importer({
+        taskRunner: runner,
+        indexName,
+        downloader: {
+          async download() {
+            return { path: trickyFile, headers: new Headers() };
+          },
+        },
+      });
+
+      const result = await importer.import(makeDistributions());
+
+      expect(result).toBeInstanceOf(ImportSuccessful);
+
+      const command = runner.commands[0];
+      // The apostrophe is POSIX-escaped, not left to break the quoting.
+      expect(command).toContain(
+        "Dataset+Beeldbank+Erfgoed+'\\''s-Hertogenbosch.ttl",
+      );
+      expect(command).not.toContain("Erfgoed+'s"); // the broken, unescaped form
+
+      // And the decompress sub-command actually reads the real file when a shell
+      // runs it — this is what produced empty input (0 triples) before the fix.
+      const decompress = command.slice(0, command.indexOf('| qlever-index'));
+      const output = execFileSync('sh', ['-c', decompress], {
+        cwd: tempDir,
+      }).toString();
+      expect(output).toContain('http://example.com/source');
+    });
+
     it('falls back to file extension when Content-Type is a compression type', async () => {
       const nqFile = join(tempDir, 'data.nq');
       await copyFile(dataFile, nqFile);
diff --git a/packages/sparql-qlever/vite.config.ts b/packages/sparql-qlever/vite.config.ts
index 6ebd10a8..45abe22c 100644
--- a/packages/sparql-qlever/vite.config.ts
+++ b/packages/sparql-qlever/vite.config.ts
@@ -13,10 +13,10 @@ export default mergeConfig(
       coverage: {
         thresholds: {
           autoUpdate: true,
-          lines: 93.81,
+          lines: 95.55,
           functions: 100,
-          branches: 80.64,
-          statements: 93.87,
+          branches: 83.87,
+          statements: 95.6,
         },
       },
     },