diff --git a/code/frontend/src/components/ParticipantsList.jsx b/code/frontend/src/components/ParticipantsList.jsx
new file mode 100644
index 0000000..15122f6
--- /dev/null
+++ b/code/frontend/src/components/ParticipantsList.jsx
@@ -0,0 +1,150 @@
+import { useState } from "react";
+import { Collapse } from "@mui/material";
+import { activityService } from "../services/activityService";
+
+const ParticipantsList = ({ activityId, onError }) => {
+  const [participants, setParticipants] = useState(null);
+  const [isExpanded, setIsExpanded] = useState(false);
+  const [isLoading, setIsLoading] = useState(false);
+
+  const fetchParticipants = async () => {
+    if (participants) return; // Already loaded
+    
+    setIsLoading(true);
+    try {
+      const response = await activityService.getActivityParticipants(activityId);
+      setParticipants(response.content || []);
+    } catch (error) {
+      console.error("Failed to fetch participants:", error);
+      onError?.("Failed to load participants");
+    } finally {
+      setIsLoading(false);
+    }
+  };
+
+  const toggleExpand = async () => {
+    const wasExpanded = isExpanded;
+    setIsExpanded(!wasExpanded);
+    
+    if (!wasExpanded && !participants) {
+      await fetchParticipants();
+    }
+  };
+
+  return (
+    <>
+      <button style={styles.participantsButton} onClick={toggleExpand}>
+        {isExpanded ? "Hide Participants" : "Show Participants"}
+      </button>
+      <Collapse in={isExpanded}>
+        <div style={styles.participantsSection}>
+          <h4 style={styles.participantsTitle}>Participants:</h4>
+          {isLoading ? (
+            <div style={styles.loadingText}>Loading participants...</div>
+          ) : participants && participants.length > 0 ? (
+            <div style={styles.participantsList}>
+              {participants.map((participant, index) => (
+                <div key={index} style={styles.participantItem}>
+                  <div style={styles.participantAvatar}>
+                    {participant.username.charAt(0).toUpperCase()}
+                  </div>
+                  <div style={styles.participantInfo}>
+                    <span style={styles.participantName}>{participant.username}</span>
+                    {participant.roleType === "ADMIN" && (
+                      <span style={styles.adminBadge}>Admin</span>
+                    )}
+                  </div>
+                </div>
+              ))}
+            </div>
+          ) : participants && participants.length === 0 ? (
+            <div style={styles.loadingText}>No participants found</div>
+          ) : null}
+        </div>
+      </Collapse>
+    </>
+  );
+};
+
+const styles = {
+  participantsButton: {
+    backgroundColor: "#6b7280",
+    color: "white",
+    border: "none",
+    padding: "0.75rem 1rem",
+    borderRadius: "0.5rem",
+    fontSize: "0.85rem",
+    fontWeight: "600",
+    cursor: "pointer",
+    transition: "background-color 0.2s",
+    flex: "1",
+    whiteSpace: "nowrap",
+  },
+  participantsSection: {
+    marginTop: "1rem",
+    padding: "1rem",
+    backgroundColor: "#f9fafb",
+    borderRadius: "0.5rem",
+    border: "1px solid #e5e7eb",
+  },
+  participantsTitle: {
+    margin: "0 0 0.75rem 0",
+    color: "#374151",
+    fontSize: "1rem",
+    fontWeight: "600",
+  },
+  participantsList: {
+    display: "flex",
+    flexDirection: "column",
+    gap: "0.5rem",
+  },
+  participantItem: {
+    display: "flex",
+    alignItems: "center",
+    gap: "0.75rem",
+    padding: "0.5rem",
+    backgroundColor: "white",
+    borderRadius: "0.375rem",
+    border: "1px solid #e5e7eb",
+  },
+  participantAvatar: {
+    width: "32px",
+    height: "32px",
+    backgroundColor: "#3b82f6",
+    color: "white",
+    borderRadius: "50%",
+    display: "flex",
+    alignItems: "center",
+    justifyContent: "center",
+    fontWeight: "bold",
+    fontSize: "0.875rem",
+  },
+  participantInfo: {
+    display: "flex",
+    alignItems: "center",
+    gap: "0.5rem",
+    flex: "1",
+  },
+  participantName: {
+    color: "#1f2937",
+    fontSize: "0.9rem",
+    fontWeight: "500",
+  },
+  adminBadge: {
+    backgroundColor: "#fbbf24",
+    color: "#92400e",
+    padding: "0.125rem 0.5rem",
+    borderRadius: "0.25rem",
+    fontSize: "0.75rem",
+    fontWeight: "600",
+  },
+  loadingText: {
+    color: "#6b7280",
+    fontSize: "0.875rem",
+    fontStyle: "italic",
+    textAlign: "center",
+    padding: "1rem",
+  },
+};
+
+export default ParticipantsList; 
\ No newline at end of file
diff --git a/code/frontend/src/pages/Home.jsx b/code/frontend/src/pages/Home.jsx
index 617e315..b7aa5de 100644
--- a/code/frontend/src/pages/Home.jsx
+++ b/code/frontend/src/pages/Home.jsx
@@ -6,6 +6,7 @@ import { styled } from "@mui/material/styles";
 import LogoutIcon from "@mui/icons-material/Logout";
 import { activityService } from "../services/activityService";
 import AvatarUpload from "../components/Avator";
+import ParticipantsList from "../components/ParticipantsList";
 
 const StyledTab = styled(Tab)({
   textTransform: "none",
@@ -388,14 +389,24 @@ export default function Home() {
                         <span>{activity.location}</span>
                       </div>
                     </div>
-                    <button
-                      style={styles.joinButton}
-                      onClick={() =>
-                        isAdmin ? handleDeleteActivity(activity.activityId) : handleLeaveActivity(activity.activityId)
-                      }
-                    >
-                      {isAdmin ? "Delete Activity" : "Leave Activity"}
-                    </button>
+                    <div style={styles.activityActions}>
+                      <ParticipantsList 
+                        activityId={activity.activityId} 
+                        onError={(message) => setNotification({
+                          open: true,
+                          message,
+                          severity: "error",
+                        })}
+                      />
+                      <button
+                        style={styles.joinButton}
+                        onClick={() =>
+                          isAdmin ? handleDeleteActivity(activity.activityId) : handleLeaveActivity(activity.activityId)
+                        }
+                      >
+                        {isAdmin ? "Delete Activity" : "Leave Activity"}
+                      </button>
+                    </div>
                   </div>
                 );
               })}
@@ -643,18 +654,28 @@ const styles = {
   metaIcon: {
     fontSize: "1rem",
   },
+  activityActions: {
+    display: "flex",
+    flexDirection: "column",
+    gap: "0.5rem",
+    marginTop: "auto",
+    alignItems: "stretch",
+  },
   joinButton: {
     backgroundColor: "#3b82f6",
     color: "white",
     border: "none",
-    padding: "0.75rem 1.5rem",
+    padding: "0.5rem 0.75rem",
     borderRadius: "0.5rem",
-    fontSize: "0.9rem",
+    fontSize: "0.95rem",
     fontWeight: "600",
     cursor: "pointer",
     transition: "background-color 0.2s",
     width: "100%",
+    minWidth: "120px",
+    maxWidth: "200px",
     alignSelf: "center",
-    marginTop: "auto",
+    margin: "0 auto",
+    boxSizing: "border-box",
   },
 };
diff --git a/code/frontend/src/services/activityService.js b/code/frontend/src/services/activityService.js
index 4562ac8..7f494b5 100644
--- a/code/frontend/src/services/activityService.js
+++ b/code/frontend/src/services/activityService.js
@@ -52,4 +52,10 @@ export const activityService = {
     const response = await api.post("/activity", activityData);
     return response.data;
   },
+  getActivityParticipants: async (activityId, page = 0, size = 20) => {
+    const response = await api.get(`/activities/${activityId}/participants`, {
+      params: { page, size }
+    });
+    return response.data.data;
+  },
 };