diff --git a/drivers/spi/spi_ll_stm32.c b/drivers/spi/spi_ll_stm32.c
index 5d56ab106b1..f6e6bf7c176 100644
--- a/drivers/spi/spi_ll_stm32.c
+++ b/drivers/spi/spi_ll_stm32.c
@@ -1186,6 +1186,13 @@ static int transceive_dma(const struct device *dev,
 	/* This is turned off in spi_stm32_complete(). */
 	spi_stm32_cs_control(dev, true);
 
+	uint8_t word_size_bytes = bits2bytes(SPI_WORD_SIZE_GET(config->operation));
+
+	data->dma_rx.dma_cfg.source_data_size = word_size_bytes;
+	data->dma_rx.dma_cfg.dest_data_size = word_size_bytes;
+	data->dma_tx.dma_cfg.source_data_size = word_size_bytes;
+	data->dma_tx.dma_cfg.dest_data_size = word_size_bytes;
+
 	while (data->ctx.rx_len > 0 || data->ctx.tx_len > 0) {
 		size_t dma_len;