Some demonstrative embodiments include apparatus, system and method of communicating a transmission according to a symbol block structure and Guard Interval (GI) scheme. For example, an apparatus may include logic and circuitry configured to cause a wireless station to generate a plurality of Single Carrier (SC) blocks according to a SC block structure corresponding to a GI type of a plurality of GI types, a SC block of the plurality of SC blocks including a GI followed by a data block, the GI including a Golay sequence having a length based at least on the GI type, a length of the data block is based at least on the GI type; and to transmit a SC transmission over a millimeter Wave (mmWave) frequency band based on the plurality of SC blocks.