diff --git a/plugins/auth-oauth1/src/index.ts b/plugins/auth-oauth1/src/index.ts
index e2f8c031..25e19b42 100644
--- a/plugins/auth-oauth1/src/index.ts
+++ b/plugins/auth-oauth1/src/index.ts
@@ -161,7 +161,7 @@ export const plugin: PluginDefinition = {
       if (values.timestamp) requestData.data.oauth_timestamp = String(values.timestamp);
       if (values.verifier) requestData.data.oauth_verifier = String(values.verifier);
 
-      let token: OAuth.Token | { key: string } | undefined;
+      let token: OAuth.Token | { key: string } | { secret: string } | undefined;
 
       if (pkSigs.includes(signatureMethod)) {
         token = {
@@ -172,6 +172,10 @@ export const plugin: PluginDefinition = {
         token = { key: String(values.tokenKey), secret: String(values.tokenSecret) };
       } else if (values.tokenKey) {
         token = { key: String(values.tokenKey) };
+      } else if (values.tokenSecret) {
+        // The secret still joins the signing key without an access token;
+        // leaving `key` out keeps oauth_token out of the header entirely
+        token = { secret: String(values.tokenSecret) };
       }
 
       const authParams = oauth.authorize(requestData, token as OAuth.Token | undefined);
diff --git a/plugins/auth-oauth1/tests/plaintext.test.ts b/plugins/auth-oauth1/tests/plaintext.test.ts
index f2517f60..e82aacbc 100644
--- a/plugins/auth-oauth1/tests/plaintext.test.ts
+++ b/plugins/auth-oauth1/tests/plaintext.test.ts
@@ -34,6 +34,21 @@ describe("PLAINTEXT signature", () => {
     expect(sign(base)).toBe("cs&");
   });
 
+  test("includes the token secret without an access token, omitting oauth_token", () => {
+    const result = plugin.authentication!.onApply!(
+      {} as never,
+      {
+        values: { ...base, tokenSecret: "ts" },
+        method: "GET",
+        url: "https://api.example.com/resource",
+      } as never,
+    ) as { setHeaders: { name: string; value: string }[] };
+    const header = result.setHeaders[0]!.value;
+    const match = header.match(/oauth_signature="([^"]*)"/);
+    expect(decodeURIComponent(match![1]!)).toBe("cs&ts");
+    expect(header).not.toContain("oauth_token=");
+  });
+
   test("percent-encodes reserved characters in the secrets", () => {
     expect(sign({ ...base, consumerSecret: "c s", tokenKey: "tk", tokenSecret: "t&s" })).toBe(
       "c%20s&t%26s",