Methods, apparatus, and systems for coupling an airbag inflator with a housing, such as an airbag module housing or an adapter housing configured to be coupled with an airbag module housing. In some implementations, a housing comprising an opening may be provided. An inflator comprising a collar may be positioned in the housing such that the collar of the inflator extends into, or in some cases through, the opening of the housing. The inflator may be fixedly coupled with the housing by engaging an exterior surface of the inflator collar with at least one engagement structure, such as a retainer clip or crimp formed in a collar sleeve of the housing.