Narrative:

Pushed off gate with 2 other aircraft pushing simultaneously [nearby] - all of us - tail north onto foxtrot. After 'before taxi/taxi' checklist we were cleared (by ramp) to 'follow the rj ahead on foxtrot to runway xxl'. I looked over just as a rj went past us on bravo (enroute to runway xxl); asked if we were clear right and pulled onto bravo to follow the rj. (Ramp meant for us to follow the rj that pushed off other gate). The first officer caught the mistake immediately and contacted ground to tell them we were entering bravo. The controller politely informed us that we shouldn't enter an active taxiway without permission; and we continued down bravo to runway xxl without incident.I believe the following items contributed to my incorrect decision:1. A ramp clearance that included a runway lead my thinking to the runway rather than the ramp taxiway 'foxtrot' (which ends at 'bravo' near the end of runway xxl).2. An rj coincidentally crossing in front of us on bravo just as we received the clearance.

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Original NASA ASRS Text

Title: A B737-800 crew pushed back then was issued a Ramp Control clearance to follow a regional jet to the runway. The Captain thinking the ATC clearance was issued to the runway; began taxiing and incurred a taxiway before contacting Ground.

Narrative: Pushed off gate with 2 other aircraft pushing simultaneously [nearby] - all of us - Tail North onto Foxtrot. After 'Before Taxi/Taxi' checklist we were cleared (by Ramp) to 'follow the RJ ahead on Foxtrot to Runway XXL'. I looked over just as a RJ went past us on Bravo (enroute to Runway XXL); asked if we were clear right and pulled onto Bravo to follow the RJ. (Ramp meant for us to follow the RJ that pushed off other gate). The FO caught the mistake immediately and contacted ground to tell them we were entering Bravo. The controller politely informed us that we shouldn't enter an active taxiway without permission; and we continued down Bravo to Runway XXL without incident.I believe the following items contributed to my incorrect decision:1. A Ramp clearance that included a runway lead my thinking to the runway rather than the ramp taxiway 'Foxtrot' (which ends at 'Bravo' near the end of Runway XXL).2. An RJ coincidentally crossing in front of us on Bravo just as we received the clearance.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.