diff --git a/include/zephyr/posix/signal.h b/include/zephyr/posix/signal.h
index 0da478b02e4c685..6a526a51cd95295 100644
--- a/include/zephyr/posix/signal.h
+++ b/include/zephyr/posix/signal.h
@@ -63,6 +63,7 @@ int sigemptyset(sigset_t *set);
 int sigfillset(sigset_t *set);
 int sigaddset(sigset_t *set, int signo);
 int sigdelset(sigset_t *set, int signo);
+int sigismember(const sigset_t *set, int signo);
 #endif /* CONFIG_POSIX_SIGNAL */
 
 #ifndef SIGEV_NONE
diff --git a/lib/posix/signal.c b/lib/posix/signal.c
index 3507cdce6748de3..35310c747754d91 100644
--- a/lib/posix/signal.c
+++ b/lib/posix/signal.c
@@ -61,3 +61,13 @@ int sigdelset(sigset_t *set, int signo)
 
 	return 0;
 }
+
+int sigismember(const sigset_t *set, int signo)
+{
+	if (signo_invalid(signo)) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	return 1 & (set->sig[signo_word_idx(signo)] >> signo_word_bit(signo));
+}
diff --git a/tests/posix/common/src/signal.c b/tests/posix/common/src/signal.c
index ade91d2e03f371e..876bae50f5d64c7 100644
--- a/tests/posix/common/src/signal.c
+++ b/tests/posix/common/src/signal.c
@@ -200,3 +200,42 @@ ZTEST(posix_apis, test_signal_delset_32)
 		      1, ARRAY_SIZE(set.sig), set.sig[1], sig_mask[1]);
 }
 #endif /* CONFIG_64BIT */
+
+ZTEST(posix_apis, test_signal_ismember_oor)
+{
+	int rc;
+	sigset_t set = {0};
+
+	rc = sigismember(&set, -1);
+	zassert_equal(rc, -1, "rc should be -1");
+	zassert_equal(errno, EINVAL, "errno should be %s", "EINVAL");
+
+	rc = sigismember(&set, 0);
+	zassert_equal(rc, -1, "rc should be -1");
+	zassert_equal(errno, EINVAL, "errno should be %s", "EINVAL");
+
+	rc = sigismember(&set, _NSIG + 1);
+	zassert_equal(rc, -1, "rc should be -1");
+	zassert_equal(errno, EINVAL, "errno should be %s", "EINVAL");
+}
+
+ZTEST(posix_apis, test_signal_ismember)
+{
+	sigset_t set;
+
+#ifdef CONFIG_64BIT
+	set.sig[0] = BIT(SIGHUP - 1) | BIT(SIGRTMIN - 1) | BIT(SIGRTMIN) | BIT(SIGRTMAX - 1);
+#else /* 32BIT */
+	set.sig[0] = BIT(SIGHUP - 1) | BIT(SIGRTMIN - 1);
+	set.sig[1] = BIT(SIGRTMIN % BITS_PER_LONG) | BIT((SIGRTMAX - 1) % BITS_PER_LONG);
+#endif
+
+	zassert_equal(sigismember(&set, SIGHUP), 1, "%s expected to be member", "SIGHUP");
+	zassert_equal(sigismember(&set, SIGRTMIN), 1, "%s expected to be member", "SIGRTMIN");
+	zassert_equal(sigismember(&set, SIGRTMIN + 1), 1, "%s expected to be member",
+		      "SIGRTMIN + 1");
+	zassert_equal(sigismember(&set, SIGRTMAX), 1, "%s expected to be member", "SIGRTMAX");
+
+	zassert_equal(sigismember(&set, SIGKILL), 0, "%s not expected to be member", "SIGKILL");
+	zassert_equal(sigismember(&set, SIGTERM), 0, "%s not expected to be member", "SIGTERM");
+}