diff --git a/src/exchanges/lighter/gateway.ts b/src/exchanges/lighter/gateway.ts
index 9ec937e..d8daa7a 100644
--- a/src/exchanges/lighter/gateway.ts
+++ b/src/exchanges/lighter/gateway.ts
@@ -905,13 +905,18 @@ export class LighterGateway {
       candidates = preferred;
     }
 
+    const preferSpot = wantsSpot;
     candidates.sort((a, b) => {
       const aExact = normalizeSymbolForms(a.symbol).includes(desiredSymbol.toUpperCase()) ? 1 : 0;
       const bExact = normalizeSymbolForms(b.symbol).includes(desiredSymbol.toUpperCase()) ? 1 : 0;
       if (aExact !== bExact) return bExact - aExact;
       const aSpot = normalizeMarketType(a.market_type) === "spot" ? 1 : 0;
       const bSpot = normalizeMarketType(b.market_type) === "spot" ? 1 : 0;
-      if (aSpot !== bSpot) return bSpot - aSpot;
+      if (aSpot !== bSpot) {
+        const aScore = preferSpot ? aSpot : 1 - aSpot; // prefer perp when not explicitly spot
+        const bScore = preferSpot ? bSpot : 1 - bSpot;
+        return bScore - aScore;
+      }
       return 0;
     });
 
diff --git a/tests/lighter/order-book-choice.test.ts b/tests/lighter/order-book-choice.test.ts
new file mode 100644
index 0000000..be7a07d
--- /dev/null
+++ b/tests/lighter/order-book-choice.test.ts
@@ -0,0 +1,40 @@
+import { describe, expect, it } from "vitest";
+import type { LighterOrderBookMetadata } from "../../src/exchanges/lighter/types";
+import { LighterGateway } from "../../src/exchanges/lighter/gateway";
+
+const pickBestOrderBook = (books: LighterOrderBookMetadata[], desiredSymbol: string) =>
+  (LighterGateway.prototype as any).pickBestOrderBook.call({}, books, desiredSymbol);
+
+describe("pickBestOrderBook", () => {
+  const spotBook = {
+    market_id: 2048,
+    symbol: "ETH/USDC",
+    market_type: "spot",
+    supported_price_decimals: 2,
+    supported_size_decimals: 4,
+    min_base_amount: "0.0001",
+    min_quote_amount: "5",
+  } as LighterOrderBookMetadata;
+
+  const perpBook = {
+    market_id: 3048,
+    symbol: "ETH-PERP",
+    market_type: "perp",
+    supported_price_decimals: 2,
+    supported_size_decimals: 3,
+    min_base_amount: "0.001",
+    min_quote_amount: "5",
+  } as LighterOrderBookMetadata;
+
+  it("prefers perp when desired symbol does not explicitly request spot", () => {
+    const picked = pickBestOrderBook([spotBook, perpBook], "ETH");
+    expect(picked?.market_type).toBe("perp");
+    expect(picked?.market_id).toBe(3048);
+  });
+
+  it("still prefers spot when symbol clearly indicates spot", () => {
+    const picked = pickBestOrderBook([spotBook, perpBook], "ETH/USDC");
+    expect(picked?.market_type).toBe("spot");
+    expect(picked?.market_id).toBe(2048);
+  });
+});