diff --git a/packages/better-auth/src/plugins/organization/adapter.ts b/packages/better-auth/src/plugins/organization/adapter.ts
index 92190b0011..6721cf7822 100644
--- a/packages/better-auth/src/plugins/organization/adapter.ts
+++ b/packages/better-auth/src/plugins/organization/adapter.ts
@@ -129,6 +129,7 @@ export const getOrgAdapter = (
 						value: data.organizationId,
 					},
 				],
+				limit: options?.membershipLimit || 100,
 			});
 			return members;
 		},
@@ -356,6 +357,7 @@ export const getOrgAdapter = (
 				adapter.findMany<Member>({
 					model: "member",
 					where: [{ field: "organizationId", value: org.id }],
+					limit: options?.membershipLimit || 100,
 				}),
 				includeTeams
 					? adapter.findMany<Team>({
@@ -408,6 +410,7 @@ export const getOrgAdapter = (
 						value: userId,
 					},
 				],
+				limit: options?.membershipLimit || 100,
 			});
 
 			if (!members || members.length === 0) {
diff --git a/packages/better-auth/src/plugins/organization/error-codes.ts b/packages/better-auth/src/plugins/organization/error-codes.ts
index e9cf4a7573..ce4c03dff1 100644
--- a/packages/better-auth/src/plugins/organization/error-codes.ts
+++ b/packages/better-auth/src/plugins/organization/error-codes.ts
@@ -43,4 +43,6 @@ export const ORGANIZATION_ERROR_CODES = {
 	UNABLE_TO_REMOVE_LAST_TEAM: "Unable to remove last team",
 	YOU_ARE_NOT_ALLOWED_TO_UPDATE_THIS_MEMBER:
 		"You are not allowed to update this member",
+	ORGANIZATION_MEMBERSHIP_LIMIT_REACHED:
+		"Organization membership limit reached",
 } as const;
diff --git a/packages/better-auth/src/plugins/organization/organization.test.ts b/packages/better-auth/src/plugins/organization/organization.test.ts
index 98e0e1c49a..527e4182af 100644
--- a/packages/better-auth/src/plugins/organization/organization.test.ts
+++ b/packages/better-auth/src/plugins/organization/organization.test.ts
@@ -6,6 +6,7 @@ import { organizationClient } from "./client";
 import { createAccessControl } from "../access";
 import { ORGANIZATION_ERROR_CODES } from "./error-codes";
 import { BetterAuthError } from "../../error";
+import { APIError } from "better-call";
 
 describe("organization", async (it) => {
 	const { auth, signInWithTestUser, signInWithUser, cookieSetter } =
@@ -15,6 +16,7 @@ describe("organization", async (it) => {
 			},
 			plugins: [
 				organization({
+					membershipLimit: 6,
 					async sendInvitationEmail(data, request) {},
 					schema: {
 						organization: {
@@ -525,6 +527,120 @@ describe("organization", async (it) => {
 		});
 		expect(member?.role).toBe("admin");
 	});
+
+	it("should respect membershipLimit when adding members to organization", async () => {
+		const org = await auth.api.createOrganization({
+			body: {
+				name: "test-5-membership-limit",
+				slug: "test-5-membership-limit",
+			},
+			headers,
+		});
+
+		const users = [
+			"user1@emial.com",
+			"user2@email.com",
+			"user3@email.com",
+			"user4@email.com",
+		];
+
+		for (const user of users) {
+			const newUser = await auth.api.signUpEmail({
+				body: {
+					email: user,
+					password: "password",
+					name: user,
+				},
+			});
+			const session = await auth.api.getSession({
+				headers: new Headers({
+					Authorization: `Bearer ${newUser?.token}`,
+				}),
+			});
+			await auth.api.addMember({
+				body: {
+					organizationId: org?.id,
+					userId: session?.user.id!,
+					role: "admin",
+				},
+			});
+		}
+
+		const userOverLimit = {
+			email: "shouldthrowerror@email.com",
+			password: "password",
+			name: "name",
+		};
+
+		// test api method
+		const newUser = await auth.api.signUpEmail({
+			body: {
+				email: userOverLimit.email,
+				password: userOverLimit.password,
+				name: userOverLimit.name,
+			},
+		});
+		const session = await auth.api.getSession({
+			headers: new Headers({
+				Authorization: `Bearer ${newUser?.token}`,
+			}),
+		});
+		await auth.api
+			.addMember({
+				body: {
+					organizationId: org?.id,
+					userId: session?.user.id!,
+					role: "admin",
+				},
+			})
+			.catch((e: APIError) => {
+				expect(e).not.toBeNull();
+				expect(e).toBeInstanceOf(APIError);
+				expect(e.message).toBe(
+					ORGANIZATION_ERROR_CODES.ORGANIZATION_MEMBERSHIP_LIMIT_REACHED,
+				);
+			});
+
+		// test client method
+		const invite = await client.organization.inviteMember({
+			organizationId: org?.id,
+			email: userOverLimit.email,
+			role: "member",
+			fetchOptions: {
+				headers,
+			},
+		});
+		if (!invite.data) throw new Error("Invitation not created");
+		await client.signUp.email({
+			email: userOverLimit.email,
+			password: userOverLimit.password,
+			name: userOverLimit.name,
+		});
+		const { res, headers: headers2 } = await signInWithUser(
+			userOverLimit.email,
+			userOverLimit.password,
+		);
+
+		const invitation = await client.organization.acceptInvitation({
+			invitationId: invite.data.id,
+			fetchOptions: {
+				headers: headers2,
+			},
+		});
+		expect(invitation.error?.message).toBe(
+			ORGANIZATION_ERROR_CODES.ORGANIZATION_MEMBERSHIP_LIMIT_REACHED,
+		);
+
+		const getFullOrganization = await client.organization.getFullOrganization({
+			query: {
+				organizationId: org?.id,
+			},
+			fetchOptions: {
+				headers,
+			},
+		});
+		expect(getFullOrganization.data?.members.length).toBe(6);
+	});
 });
 
 describe("access control", async (it) => {
diff --git a/packages/better-auth/src/plugins/organization/organization.ts b/packages/better-auth/src/plugins/organization/organization.ts
index b1b228c6aa..68d607bb74 100644
--- a/packages/better-auth/src/plugins/organization/organization.ts
+++ b/packages/better-auth/src/plugins/organization/organization.ts
@@ -83,7 +83,7 @@ export interface OrganizationOptions {
 	/**
 	 * The number of memberships a user can have in an organization.
 	 *
-	 * @default "unlimited"
+	 * @default 100
 	 */
 	membershipLimit?: number;
 	/**
diff --git a/packages/better-auth/src/plugins/organization/routes/crud-invites.ts b/packages/better-auth/src/plugins/organization/routes/crud-invites.ts
index a698e753e3..4c7db38184 100644
--- a/packages/better-auth/src/plugins/organization/routes/crud-invites.ts
+++ b/packages/better-auth/src/plugins/organization/routes/crud-invites.ts
@@ -290,6 +290,16 @@ export const acceptInvitation = createAuthEndpoint(
 					ORGANIZATION_ERROR_CODES.YOU_ARE_NOT_THE_RECIPIENT_OF_THE_INVITATION,
 			});
 		}
+		const membershipLimit = ctx.context.orgOptions?.membershipLimit || 100;
+		const members = await adapter.listMembers({
+			organizationId: invitation.organizationId,
+		});
+
+		if (members.length >= membershipLimit) {
+			throw new APIError("FORBIDDEN", {
+				message: ORGANIZATION_ERROR_CODES.ORGANIZATION_MEMBERSHIP_LIMIT_REACHED,
+			});
+		}
 		const acceptedI = await adapter.updateInvitation({
 			invitationId: ctx.body.invitationId,
 			status: "accepted",
diff --git a/packages/better-auth/src/plugins/organization/routes/crud-members.ts b/packages/better-auth/src/plugins/organization/routes/crud-members.ts
index 40ac2c608b..01137d5119 100644
--- a/packages/better-auth/src/plugins/organization/routes/crud-members.ts
+++ b/packages/better-auth/src/plugins/organization/routes/crud-members.ts
@@ -64,6 +64,7 @@ export const addMember = <O extends OrganizationOptions>() =>
 				email: user.email,
 				organizationId: orgId,
 			});
+
 			if (alreadyMember) {
 				throw new APIError("BAD_REQUEST", {
 					message:
@@ -71,6 +72,16 @@ export const addMember = <O extends OrganizationOptions>() =>
 				});
 			}
 
+			const membershipLimit = ctx.context.orgOptions?.membershipLimit || 100;
+			const members = await adapter.listMembers({ organizationId: orgId });
+
+			if (members.length >= membershipLimit) {
+				throw new APIError("FORBIDDEN", {
+					message:
+						ORGANIZATION_ERROR_CODES.ORGANIZATION_MEMBERSHIP_LIMIT_REACHED,
+				});
+			}
+
 			const createdMember = await adapter.createMember({
 				id: generateId(),
 				organizationId: orgId,