diff --git a/include/mbedtls/memory_buffer_alloc.h b/include/mbedtls/memory_buffer_alloc.h
index 3408f343b..5e14823b7 100644
--- a/include/mbedtls/memory_buffer_alloc.h
+++ b/include/mbedtls/memory_buffer_alloc.h
@@ -127,7 +127,7 @@ void mbedtls_memory_buffer_alloc_cur_get( size_t *cur_used, size_t *cur_blocks )
  *          is defined. (Includes stack trace information for each block if
  *          MBEDTLS_MEMORY_BACKTRACE is defined as well).
  *
- * \returns             0 if verified, 1 otherwise
+ * \return             0 if verified, 1 otherwise
  */
 int mbedtls_memory_buffer_alloc_verify( void );
 
diff --git a/include/mbedtls/net.h b/include/mbedtls/net.h
index 9f757fef0..586bd34ab 100644
--- a/include/mbedtls/net.h
+++ b/include/mbedtls/net.h
@@ -149,7 +149,7 @@ void mbedtls_net_usleep( unsigned long usec );
  * \param buf      The buffer to write to
  * \param len      Maximum length of the buffer
  *
- * \return         This function returns the number of bytes received,
+ * \return         the number of bytes received,
  *                 or a non-zero error code; with a non-blocking socket,
  *                 MBEDTLS_ERR_SSL_WANT_READ indicates read() would block.
  */
@@ -163,7 +163,7 @@ int mbedtls_net_recv( void *ctx, unsigned char *buf, size_t len );
  * \param buf      The buffer to read from
  * \param len      The length of the buffer
  *
- * \return         This function returns the number of bytes sent,
+ * \return         the number of bytes sent,
  *                 or a non-zero error code; with a non-blocking socket,
  *                 MBEDTLS_ERR_SSL_WANT_WRITE indicates write() would block.
  */
@@ -179,7 +179,7 @@ int mbedtls_net_send( void *ctx, const unsigned char *buf, size_t len );
  * \param len      Maximum length of the buffer
  * \param timeout  Maximum number of milliseconds to wait for data
  *
- * \return         This function returns the number of bytes received,
+ * \return         the number of bytes received,
  *                 or a non-zero error code:
  *                 MBEDTLS_ERR_SSL_TIMEOUT if the operation timed out,
  *                 MBEDTLS_ERR_SSL_WANT_READ if interrupted by a signal.
diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index 4586fc099..ffd06dd33 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -546,7 +546,7 @@ int mbedtls_pk_write_pubkey_der( mbedtls_pk_context *ctx, unsigned char *buf, si
  * \param buf       buffer to write to
  * \param size      size of the buffer
  *
- * \return          0 successful, or a specific error code
+ * \return          0 if successful, or a specific error code
  */
 int mbedtls_pk_write_pubkey_pem( mbedtls_pk_context *ctx, unsigned char *buf, size_t size );
 
@@ -557,7 +557,7 @@ int mbedtls_pk_write_pubkey_pem( mbedtls_pk_context *ctx, unsigned char *buf, si
  * \param buf       buffer to write to
  * \param size      size of the buffer
  *
- * \return          0 successful, or a specific error code
+ * \return          0 if successful, or a specific error code
  */
 int mbedtls_pk_write_key_pem( mbedtls_pk_context *ctx, unsigned char *buf, size_t size );
 #endif /* MBEDTLS_PEM_WRITE_C */
diff --git a/include/mbedtls/rsa.h b/include/mbedtls/rsa.h
index 15afaee6b..3898687e0 100644
--- a/include/mbedtls/rsa.h
+++ b/include/mbedtls/rsa.h
@@ -625,7 +625,7 @@ int mbedtls_rsa_rsassa_pss_verify_ext( mbedtls_rsa_context *ctx,
  * \param dst      Destination context
  * \param src      Source context
  *
- * \return         O on success,
+ * \return         0 on success,
  *                 MBEDTLS_ERR_MPI_ALLOC_FAILED on memory allocation failure
  */
 int mbedtls_rsa_copy( mbedtls_rsa_context *dst, const mbedtls_rsa_context *src );
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index bb68d76c3..b9654ba19 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -2029,8 +2029,9 @@ int mbedtls_ssl_renegotiate( mbedtls_ssl_context *ssl );
  * \param buf      buffer that will hold the data
  * \param len      maximum number of bytes to read
  *
- * \return         This function returns the number of bytes read, 0 for EOF,
- *                 or a negative error code.
+ * \return         the number of bytes read, or
+ *                 0 for EOF, or
+ *                 a negative error code.
  */
 int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len );
 
@@ -2041,7 +2042,7 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
  * \param buf      buffer holding the data
  * \param len      how many bytes must be written
  *
- * \return         This function returns the number of bytes written,
+ * \return         the number of bytes written,
  *                 or a negative error code.
  *
  * \note           When this function returns MBEDTLS_ERR_SSL_WANT_WRITE,
diff --git a/include/mbedtls/ssl_ticket.h b/include/mbedtls/ssl_ticket.h
index 36b2f4c5e..caa838089 100644
--- a/include/mbedtls/ssl_ticket.h
+++ b/include/mbedtls/ssl_ticket.h
@@ -95,7 +95,7 @@ void mbedtls_ssl_ticket_init( mbedtls_ssl_ticket_context *ctx );
  *                  least as strong as the the strongest ciphersuite
  *                  supported. Usually that means a 256-bit key.
  *
- * \return          0 is successful,
+ * \return          0 if successful,
  *                  or a specific MBEDTLS_ERR_XXX error code
  */
 int mbedtls_ssl_ticket_setup( mbedtls_ssl_ticket_context *ctx,
diff --git a/include/mbedtls/x509_crt.h b/include/mbedtls/x509_crt.h
index 19df51e7e..da5ff350b 100644
--- a/include/mbedtls/x509_crt.h
+++ b/include/mbedtls/x509_crt.h
@@ -283,7 +283,7 @@ int mbedtls_x509_crt_check_key_usage( const mbedtls_x509_crt *crt, unsigned int
  * \param usage_oid Intended usage (eg MBEDTLS_OID_SERVER_AUTH or MBEDTLS_OID_CLIENT_AUTH).
  * \param usage_len Length of usage_oid (eg given by MBEDTLS_OID_SIZE()).
  *
- * \return         0 is this use of the certificate is allowed,
+ * \return         0 if this use of the certificate is allowed,
  *                 MBEDTLS_ERR_X509_BAD_INPUT_DATA if not.
  *
  * \note           Usually only makes sense on leaf certificates.
@@ -544,7 +544,7 @@ int mbedtls_x509write_crt_der( mbedtls_x509write_cert *ctx, unsigned char *buf,
  * \param f_rng     RNG function (for signature, see note)
  * \param p_rng     RNG parameter
  *
- * \return          0 successful, or a specific error code
+ * \return          0 if successful, or a specific error code
  *
  * \note            f_rng may be NULL if RSA is used for signature and the
  *                  signature is made offline (otherwise f_rng is desirable
diff --git a/include/mbedtls/x509_csr.h b/include/mbedtls/x509_csr.h
index 7ae7d224e..b52ffff62 100644
--- a/include/mbedtls/x509_csr.h
+++ b/include/mbedtls/x509_csr.h
@@ -273,7 +273,7 @@ int mbedtls_x509write_csr_der( mbedtls_x509write_csr *ctx, unsigned char *buf, s
  * \param f_rng     RNG function (for signature, see note)
  * \param p_rng     RNG parameter
  *
- * \return          0 successful, or a specific error code
+ * \return          0 if successful, or a specific error code
  *
  * \note            f_rng may be NULL if RSA is used for signature and the
  *                  signature is made offline (otherwise f_rng is desirable