Methods, systems, and devices for data masking for memory are described. A memory device may set multiple data masking flags for associated memory array(s) at power-up. Each data masking flag may be associated with a respective page of memory cells and may indicate whether the data stored in the respective page is masked data, or whether the data is new, unmasked data. Data existing at a previous power-down may be masked until an initial write or activate command has been performed on the page after power-up, where the initial write or activate command may result in writing masked data, write data, or a combination thereof to the page. After previously stored data is overwritten to a page, the flag associated with the page may be reset, which may indicate that data stored at the page is available to be read.