diff --git a/.wolfssl_known_macro_extras b/.wolfssl_known_macro_extras
index 899a2f9cf5c..ddd42722c2d 100644
--- a/.wolfssl_known_macro_extras
+++ b/.wolfssl_known_macro_extras
@@ -1147,6 +1147,7 @@ WOLFSSL_OLD_TIMINGPADVERIFY
 WOLFSSL_OLD_UNSUPPORTED_EXTENSION
 WOLFSSL_OPENSSL_NO_BUILD_DATE
 WOLFSSL_OPTEE
+WOLFSSL_OPTEE_ASN_TIME
 WOLFSSL_OPTIONS_IGNORE_SYS
 WOLFSSL_PASSTHRU_ERR
 WOLFSSL_PB
diff --git a/src/internal.c b/src/internal.c
index b7749f7ae81..4303fc744bf 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -11998,6 +11998,17 @@ ProtocolVersion MakeDTLSv1_3(void)
     }
 #endif
 
+#elif defined(WOLFSSL_OPTEE)
+    word32 LowResTimer(void)
+    {
+        TEE_Time now;
+
+        /* Monotonic within the TA, and not the normal world's clock. */
+        TEE_GetSystemTime(&now);
+
+        return (word32)now.seconds;
+    }
+
 #elif defined(TIME_OVERRIDES)
 #if !defined(NO_ASN) && !defined(NO_ASN_TIME)
     /* use same asn time overrides unless user wants tick override above */
diff --git a/src/tls13.c b/src/tls13.c
index 7cf731a3d2f..b7b2420bcfe 100644
--- a/src/tls13.c
+++ b/src/tls13.c
@@ -2117,6 +2117,17 @@ int DeriveTls13Keys(WOLFSSL* ssl, int secret, int side, int store)
     }
 #endif
 
+#elif defined(WOLFSSL_OPTEE)
+    word32 TimeNowInMilliseconds(void)
+    {
+        TEE_Time now;
+
+        /* Monotonic within the TA, and not the normal world's clock. */
+        TEE_GetSystemTime(&now);
+
+        return (word32)((now.seconds * 1000) + now.millis);
+    }
+
 #elif defined(TIME_OVERRIDES)
 #if !defined(NO_ASN) && !defined(NO_ASN_TIME)
     word32 TimeNowInMilliseconds(void)
@@ -2400,6 +2411,17 @@ int DeriveTls13Keys(WOLFSSL* ssl, int secret, int side, int store)
     }
 #endif
 
+#elif defined(WOLFSSL_OPTEE)
+    sword64 TimeNowInMilliseconds(void)
+    {
+        TEE_Time now;
+
+        /* Monotonic within the TA, and not the normal world's clock. */
+        TEE_GetSystemTime(&now);
+
+        return ((sword64)now.seconds * 1000) + (sword64)now.millis;
+    }
+
 #elif defined(TIME_OVERRIDES)
 #if !defined(NO_ASN) && !defined(NO_ASN_TIME)
     sword64 TimeNowInMilliseconds(void)
diff --git a/wolfcrypt/benchmark/benchmark.c b/wolfcrypt/benchmark/benchmark.c
index 0833afb7921..ec4b104b74d 100644
--- a/wolfcrypt/benchmark/benchmark.c
+++ b/wolfcrypt/benchmark/benchmark.c
@@ -19013,6 +19013,20 @@ void bench_mldsaKeySign(byte level)
         return ret;
 #endif
     }
+#elif defined(WOLFSSL_OPTEE)
+
+    double current_time(int reset)
+    {
+        TEE_Time now;
+
+        (void)reset;
+
+        /* Millisecond granularity, so short operations need iterations. */
+        TEE_GetSystemTime(&now);
+
+        return (double)now.seconds + ((double)now.millis / 1000.0);
+    }
+
 #elif defined(WOLFSSL_ZEPHYR)
 
     #include <time.h>
diff --git a/wolfcrypt/src/cpuid.c b/wolfcrypt/src/cpuid.c
index d4ceb4c9d9f..df47a611935 100644
--- a/wolfcrypt/src/cpuid.c
+++ b/wolfcrypt/src/cpuid.c
@@ -333,7 +333,10 @@
                 (&cpuid_flags, &old_cpuid_flags, new_cpuid_flags);
         }
     }
-#elif defined(__linux__)
+/* A trusted application is cross compiled with a Linux toolchain that
+ * predefines __linux__, but libutee has no getauxval, so it takes the
+ * compiled-in flags below instead. */
+#elif defined(__linux__) && !defined(WOLFSSL_OPTEE)
     /* https://community.arm.com/arm-community-blogs/b/operating-systems-blog/
      * posts/runtime-detection-of-cpu-features-on-an-armv8-a-cpu */
 
diff --git a/wolfcrypt/src/random.c b/wolfcrypt/src/random.c
index 23b7eb2b744..3e64bf62907 100644
--- a/wolfcrypt/src/random.c
+++ b/wolfcrypt/src/random.c
@@ -221,6 +221,9 @@ This library contains implementation for the random number generator.
 #elif defined(WOLFSSL_DEOS)
 #elif defined(MICRIUM)
 #elif defined(WOLFSSL_NUCLEUS)
+#elif defined(WOLFSSL_OPTEE)
+    /* for TEE_GenerateRandom */
+    #include <tee_internal_api.h>
 #elif defined(WOLFSSL_PB)
 #elif defined(WOLFSSL_ZEPHYR)
 #elif defined(WOLFSSL_TELIT_M2MB)
@@ -10626,6 +10629,19 @@ int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
         return 0;
     }
 
+#elif defined(WOLFSSL_OPTEE)
+
+    /* Seeds the DRBG rather than replacing it; a build wanting the TEE RNG
+     * directly can still set CUSTOM_RAND_GENERATE_BLOCK. */
+    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
+    {
+        (void)os;
+
+        TEE_GenerateRandom(output, (size_t)sz);
+
+        return 0;
+    }
+
 #elif defined(WOLFSSL_PB)
 
     int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
diff --git a/wolfcrypt/src/wc_port.c b/wolfcrypt/src/wc_port.c
index 20263890bc1..33497227fe9 100644
--- a/wolfcrypt/src/wc_port.c
+++ b/wolfcrypt/src/wc_port.c
@@ -4940,6 +4940,25 @@ time_t fsl_time(time_t* t)
 }
 #endif
 
+/* Matches the XTIME mapping's gate in wc_port.h, so this is not built when
+ * that mapping is excluded. */
+#if defined(WOLFSSL_OPTEE) && !defined(NO_ASN_TIME)
+
+time_t optee_time(time_t* timer)
+{
+    TEE_Time reeTime;
+
+    /* Normal-world clock, so not a trusted time source. See wc_port.h. */
+    TEE_GetREETime(&reeTime);
+
+    if (timer != NULL)
+        *timer = (time_t)reeTime.seconds;
+
+    return (time_t)reeTime.seconds;
+}
+
+#endif /* WOLFSSL_OPTEE && !NO_ASN_TIME */
+
 #if defined(MICRIUM)
 
 time_t micrium_time(time_t* timer)
diff --git a/wolfssl/wolfcrypt/settings.h b/wolfssl/wolfcrypt/settings.h
index 0400501fcb6..b25f56b5b04 100644
--- a/wolfssl/wolfcrypt/settings.h
+++ b/wolfssl/wolfcrypt/settings.h
@@ -3525,8 +3525,15 @@
     #define NO_WRITEV
     #define NO_MAIN_DRIVER
     #define SINGLE_THREADED
-    #define NO_ASN_TIME /* no wall clock in a TA */
-    #define USER_TICKS
+    /* The only wall clock a trusted application can reach belongs to the
+     * normal world, so certificate dates are off by default. A project that
+     * accepts that clock defines WOLFSSL_OPTEE_ASN_TIME, which turns on XTIME
+     * from TEE_GetREETime and the TEE_GetSystemTime timers. USER_TICKS is not
+     * set either way, since those timers are supplied here; a project may
+     * still define it to override them. */
+    #ifndef WOLFSSL_OPTEE_ASN_TIME
+        #define NO_ASN_TIME
+    #endif
 #endif /* WOLFSSL_OPTEE */
 
 /* FreeScale MMCAU hardware crypto has 4 byte alignment.
diff --git a/wolfssl/wolfcrypt/types.h b/wolfssl/wolfcrypt/types.h
index b4b67cd1f33..c500df58244 100644
--- a/wolfssl/wolfcrypt/types.h
+++ b/wolfssl/wolfcrypt/types.h
@@ -833,6 +833,22 @@ enum {
     #endif
     #define XREALLOC(p, n, h, t) m2mb_os_realloc((p), (n))
 
+#elif defined(WOLFSSL_OPTEE)
+    /* libutee rather than a C library, so no std heap. FILL_ZERO because a
+     * trusted application holds key material. */
+    #include <tee_internal_api.h>
+    #define XMALLOC(s, h, t)     ((void)(h), (void)(t), \
+        TEE_Malloc((size_t)(s), TEE_MALLOC_FILL_ZERO))
+    #ifdef WOLFSSL_XFREE_NO_NULLNESS_CHECK
+        #define XFREE(p, h, t)   do { (void)(h); (void)(t); \
+            TEE_Free(p); } while (0)
+    #else
+        #define XFREE(p, h, t)   do { void* xp = (p); (void)(h); (void)(t); \
+            if (xp != NULL) TEE_Free(xp); } while (0)
+    #endif
+    #define XREALLOC(p, n, h, t) ((void)(h), (void)(t), \
+        TEE_Realloc((p), (size_t)(n)))
+
 #elif defined(NO_WOLFSSL_MEMORY)
     #ifdef WOLFSSL_NO_MALLOC
         /* this platform does not support heap use */
diff --git a/wolfssl/wolfcrypt/wc_port.h b/wolfssl/wolfcrypt/wc_port.h
index d61ee49f6cb..0dbb0d1f38c 100644
--- a/wolfssl/wolfcrypt/wc_port.h
+++ b/wolfssl/wolfcrypt/wc_port.h
@@ -1772,6 +1772,18 @@ WOLFSSL_ABI WOLFSSL_API int wolfCrypt_Cleanup(void);
             extern time_t deos_time(time_t* timer);
             #define XTIME(t1) deos_time((t1))
         #endif
+#elif defined(WOLFSSL_OPTEE)
+    #include <time.h>
+    #include <tee_internal_api.h>
+    /* The normal world owns this clock, so it is attacker influenced: fit
+     * for freshness, not for certificate validity. Hence NO_ASN_TIME in the
+     * WOLFSSL_OPTEE settings block. */
+    #ifndef XTIME
+        extern time_t optee_time(time_t* timer);
+        #define XTIME(t1)   optee_time((t1))
+    #endif
+    #define WOLFSSL_GMTIME
+
 #elif defined(MICRIUM)
     #include <clk.h>
     #include <time.h>