diff --git a/src/main/java/com/dog/dognation/ai/GeminiClient.java b/src/main/java/com/dog/dognation/ai/GeminiClient.java
new file mode 100644
index 0000000..1fe9831
--- /dev/null
+++ b/src/main/java/com/dog/dognation/ai/GeminiClient.java
@@ -0,0 +1,57 @@
+package com.dog.dognation.ai;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.RestClient;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Google Gemini(Generative Language API) 최소 클라이언트.
+ * responseSchema 로 구조화된 JSON 을 강제하고, 모델 응답 text(JSON 문자열)를 그대로 반환한다.
+ * API 키는 app.ai.gemini.api-key(=env GEMINI_API_KEY), 모델은 app.ai.gemini.model.
+ */
+@Component
+public class GeminiClient {
+
+    private static final String BASE =
+            "https://generativelanguage.googleapis.com/v1beta/models/";
+
+    private final RestClient rest = RestClient.create();
+
+    @Value("${app.ai.gemini.api-key:}")
+    private String apiKey;
+
+    @Value("${app.ai.gemini.model:gemini-flash-latest}")
+    private String model;
+
+    public boolean isConfigured() {
+        return apiKey != null && !apiKey.isBlank();
+    }
+
+    /**
+     * 프롬프트와 응답 스키마로 생성 호출하고, 모델이 반환한 JSON 문자열을 돌려준다.
+     * @param responseSchema Gemini responseSchema (OpenAPI 형식 Map)
+     */
+    public String generateJson(String prompt, Map<String, Object> responseSchema) {
+        Map<String, Object> body = Map.of(
+                "contents", List.of(Map.of("parts", List.of(Map.of("text", prompt)))),
+                "generationConfig", Map.of(
+                        "responseMimeType", "application/json",
+                        "responseSchema", responseSchema));
+
+        JsonNode res = rest.post()
+                .uri(BASE + model + ":generateContent?key={k}", apiKey)
+                .body(body)
+                .retrieve()
+                .body(JsonNode.class);
+
+        if (res == null) {
+            return "";
+        }
+        return res.path("candidates").path(0).path("content")
+                .path("parts").path(0).path("text").asText("");
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/dog/dognation/api/SpotController.java b/src/main/java/com/dog/dognation/api/SpotController.java
index 00dc9eb..4801a09 100644
--- a/src/main/java/com/dog/dognation/api/SpotController.java
+++ b/src/main/java/com/dog/dognation/api/SpotController.java
@@ -1,11 +1,13 @@
 package com.dog.dognation.api;
 
+import com.dog.dognation.api.dto.SpotDtos.AiMateResponse;
 import com.dog.dognation.api.dto.SpotDtos.CheckInRequest;
 import com.dog.dognation.api.dto.SpotDtos.CheckInResponse;
 import com.dog.dognation.api.dto.SpotDtos.MateResponse;
 import com.dog.dognation.api.dto.SpotDtos.ReviewCreateRequest;
 import com.dog.dognation.api.dto.SpotDtos.ReviewResponse;
 import com.dog.dognation.api.dto.SpotDtos.SpotResponse;
+import com.dog.dognation.domain.spot.MateAiService;
 import com.dog.dognation.domain.spot.SpotService;
 import jakarta.validation.Valid;
 import org.springframework.http.HttpStatus;
@@ -15,6 +17,7 @@ import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 
 import java.util.List;
@@ -24,9 +27,11 @@ import java.util.List;
 public class SpotController {
 
     private final SpotService spotService;
+    private final MateAiService mateAiService;
 
-    public SpotController(SpotService spotService) {
+    public SpotController(SpotService spotService, MateAiService mateAiService) {
         this.spotService = spotService;
+        this.mateAiService = mateAiService;
     }
 
     /** 스팟 목록 */
@@ -50,6 +55,12 @@ public class SpotController {
         return spotService.activeMates(id).stream().map(MateResponse::from).toList();
     }
 
+    /** AI 궁합 메이트 추천 — 내 강아지(dogId)와 사이좋게 지낼 만한 스팟 내 강아지 목록 */
+    @GetMapping("/{id}/ai-mates")
+    public List<AiMateResponse> aiMates(@PathVariable Long id, @RequestParam Long dogId) {
+        return mateAiService.compatibleMates(id, dogId);
+    }
+
     /** 스팟 한줄평 목록 */
     @GetMapping("/{id}/reviews")
     public List<ReviewResponse> reviews(@PathVariable Long id) {
diff --git a/src/main/java/com/dog/dognation/api/dto/SpotDtos.java b/src/main/java/com/dog/dognation/api/dto/SpotDtos.java
index 8f5b0ea..40de55d 100644
--- a/src/main/java/com/dog/dognation/api/dto/SpotDtos.java
+++ b/src/main/java/com/dog/dognation/api/dto/SpotDtos.java
@@ -26,6 +26,10 @@ public final class SpotDtos {
         }
     }
 
+    /** AI가 추천한 궁합 메이트 — 궁합점수(0-100)와 한줄 이유 포함. */
+    public record AiMateResponse(Long dogId, String name, String breed, int score, String reason) {
+    }
+
     public record ReviewResponse(Long id, String tag, String content, OffsetDateTime createdAt) {
         public static ReviewResponse from(SpotReview r) {
             return new ReviewResponse(r.getId(), r.getTag(), r.getContent(), r.getCreatedAt());
diff --git a/src/main/java/com/dog/dognation/domain/dog/DogRepository.java b/src/main/java/com/dog/dognation/domain/dog/DogRepository.java
index 6fdc799..bdf913e 100644
--- a/src/main/java/com/dog/dognation/domain/dog/DogRepository.java
+++ b/src/main/java/com/dog/dognation/domain/dog/DogRepository.java
@@ -3,6 +3,7 @@ package com.dog.dognation.domain.dog;
 import org.springframework.data.jpa.repository.EntityGraph;
 import org.springframework.data.jpa.repository.JpaRepository;
 
+import java.util.Collection;
 import java.util.List;
 import java.util.Optional;
 
@@ -14,4 +15,8 @@ public interface DogRepository extends JpaRepository<Dog, Long> {
 
     @EntityGraph(attributePaths = "traits")
     Optional<Dog> findWithTraitsById(Long id);
+
+    // AI 궁합 추천: 스팟 활성 강아지들을 성향과 함께 일괄 로딩
+    @EntityGraph(attributePaths = "traits")
+    List<Dog> findWithTraitsByIdIn(Collection<Long> ids);
 }
diff --git a/src/main/java/com/dog/dognation/domain/spot/MateAiService.java b/src/main/java/com/dog/dognation/domain/spot/MateAiService.java
new file mode 100644
index 0000000..1ace7d1
--- /dev/null
+++ b/src/main/java/com/dog/dognation/domain/spot/MateAiService.java
@@ -0,0 +1,149 @@
+package com.dog.dognation.domain.spot;
+
+import com.dog.dognation.ai.GeminiClient;
+import com.dog.dognation.api.dto.SpotDtos.AiMateResponse;
+import com.dog.dognation.common.exception.ApiException;
+import com.dog.dognation.domain.dog.Dog;
+import com.dog.dognation.domain.dog.DogRepository;
+import com.dog.dognation.domain.dog.TraitTag;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpStatus;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+/**
+ * AI(Gemini) 기반 스팟 궁합 메이트 추천.
+ * 해당 스팟에 현재 체크인 중(Redis 24h)인 강아지들 중, 내 강아지와 사이좋게 지낼 만한
+ * 강아지만 골라 궁합점수·이유와 함께 반환한다.
+ */
+@Service
+public class MateAiService {
+
+    private static final Logger log = LoggerFactory.getLogger(MateAiService.class);
+
+    /** Gemini responseSchema — [{dogId, score, reason}] 배열 강제. */
+    private static final Map<String, Object> SCHEMA = Map.of(
+            "type", "ARRAY",
+            "items", Map.of(
+                    "type", "OBJECT",
+                    "properties", Map.of(
+                            "dogId", Map.of("type", "INTEGER"),
+                            "score", Map.of("type", "INTEGER"),
+                            "reason", Map.of("type", "STRING")),
+                    "required", List.of("dogId", "score", "reason")));
+
+    private final CheckInRedisStore checkInRedisStore;
+    private final DogRepository dogRepository;
+    private final GeminiClient gemini;
+    private final ObjectMapper mapper = new ObjectMapper();
+
+    public MateAiService(CheckInRedisStore checkInRedisStore,
+                         DogRepository dogRepository,
+                         GeminiClient gemini) {
+        this.checkInRedisStore = checkInRedisStore;
+        this.dogRepository = dogRepository;
+        this.gemini = gemini;
+    }
+
+    /** 스팟 활성 메이트 중 내 강아지와 궁합 좋은 강아지 목록(궁합점수 내림차순). */
+    @Transactional(readOnly = true)
+    public List<AiMateResponse> compatibleMates(Long spotId, Long myDogId) {
+        if (!gemini.isConfigured()) {
+            throw new ApiException(HttpStatus.SERVICE_UNAVAILABLE, "AI 추천이 설정되지 않았습니다.");
+        }
+        Dog myDog = dogRepository.findWithTraitsById(myDogId)
+                .orElseThrow(() -> new ApiException(HttpStatus.NOT_FOUND, "강아지를 찾을 수 없습니다."));
+
+        List<Long> activeIds = new ArrayList<>(checkInRedisStore.activeDogIds(spotId));
+        activeIds.remove(myDogId); // 내 강아지는 제외
+        if (activeIds.isEmpty()) {
+            return List.of();
+        }
+        Map<Long, Dog> candidates = dogRepository.findWithTraitsByIdIn(activeIds).stream()
+                .collect(Collectors.toMap(Dog::getId, Function.identity()));
+        if (candidates.isEmpty()) {
+            return List.of();
+        }
+
+        String json;
+        try {
+            json = gemini.generateJson(buildPrompt(myDog, candidates.values()), SCHEMA);
+        } catch (Exception e) {
+            log.warn("[ai-mates] Gemini 호출 실패: {}", e.toString());
+            throw new ApiException(HttpStatus.BAD_GATEWAY, "AI 추천을 불러오지 못했습니다.");
+        }
+        return parse(json, candidates);
+    }
+
+    private String buildPrompt(Dog myDog, Iterable<Dog> candidates) {
+        List<Map<String, Object>> cands = new ArrayList<>();
+        for (Dog d : candidates) {
+            cands.add(dogJson(d, true));
+        }
+        try {
+            String myJson = mapper.writeValueAsString(dogJson(myDog, false));
+            String candJson = mapper.writeValueAsString(cands);
+            return """
+                    너는 반려견 산책 매칭 도우미다. 내 강아지와 공원에 있는 강아지들 중
+                    '사이좋게 지낼 만한' 강아지만 골라라. 크기 차이로 인한 두려움과
+                    성향 충돌(예: '대형견 무서워함' vs 대형견, 저에너지 vs 과잉에너지)을 고려하고,
+                    궁합이 낮은 강아지는 제외해라.
+
+                    내 강아지: %s
+                    공원의 강아지들: %s
+
+                    각 추천에 dogId, 궁합점수(0-100 정수), 한국어 한줄 이유(reason)를 담아 반환해라.
+                    """.formatted(myJson, candJson);
+        } catch (Exception e) {
+            throw new ApiException(HttpStatus.INTERNAL_SERVER_ERROR, "AI 요청 생성 실패");
+        }
+    }
+
+    private Map<String, Object> dogJson(Dog d, boolean includeId) {
+        Map<String, Object> m = new LinkedHashMap<>();
+        if (includeId) {
+            m.put("dogId", d.getId());
+        }
+        m.put("name", d.getName());
+        m.put("breed", d.getBreed());
+        m.put("size", d.getSize());
+        m.put("traits", d.getTraits().stream().map(TraitTag::getLabel).toList());
+        return m;
+    }
+
+    private List<AiMateResponse> parse(String json, Map<Long, Dog> candidates) {
+        if (json == null || json.isBlank()) {
+            return List.of();
+        }
+        try {
+            JsonNode arr = mapper.readTree(json);
+            List<AiMateResponse> out = new ArrayList<>();
+            for (JsonNode node : arr) {
+                long dogId = node.path("dogId").asLong(-1);
+                Dog dog = candidates.get(dogId);
+                if (dog == null) {
+                    continue; // 후보 밖 dogId(환각) 방지
+                }
+                int score = node.path("score").asInt(0);
+                String reason = node.path("reason").asText("");
+                out.add(new AiMateResponse(dog.getId(), dog.getName(), dog.getBreed(), score, reason));
+            }
+            out.sort(Comparator.comparingInt(AiMateResponse::score).reversed());
+            return out;
+        } catch (Exception e) {
+            log.warn("[ai-mates] 응답 파싱 실패: {}", e.toString());
+            return List.of();
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/resources/application.yml b/src/main/resources/application.yml
index 5e6eb47..d6d1742 100644
--- a/src/main/resources/application.yml
+++ b/src/main/resources/application.yml
@@ -37,6 +37,11 @@ spring:
 app:
   scheduler:
     timezone: Asia/Seoul
+  # AI 궁합 추천 (Gemini). 키 미설정 시 추천 비활성(503).
+  ai:
+    gemini:
+      api-key: ${GEMINI_API_KEY:}
+      model: ${GEMINI_MODEL:gemini-flash-latest}
   matching:
     daily-free-limit: 3
   # 소셜 로그인 — 값은 .env 에서 주입. 미설정 시 해당 로그인 비활성.