A method of forming an array of memory cells, where the array comprises an elevationally-inner tier of memory cells comprising spaced-inner-tier-lower-first-conductive lines and inner-tier-programmable material directly there-above, an elevationally-outer tier of memory cells comprising spaced-outer-tier-lower-first-conductive lines and outer-tier-programmable material directly there-above, and spaced-upper-second-conductive lines that are electrically shared by the outer-tier memory cells and the inner-tier memory cells, comprises depositing conductor material for all of the shared-spaced-upper-second-conductive lines. All of the conductor material for all of the shared-spaced-upper-second-conductive lines is patterned using only a single masking step. Other method embodiments and arrays of memory cells independent of method of manufacture are disclosed.